Trains & Bird Puzzle Brilliant Puzzle
video description
since speed = distance x times then A travel in X/ 60 and B 300- X / 90
cross multiply will give you 90 X = 1800- 60 X or 150 X = 1800
solving for X = 120,
so train A travels for 120 miles and train B for 240 miles
since both train reach at the same time from when they started and collided the time is 120/60 or 180/ 90= 2hrs.
Since it took the train 2 hours to collide, it also took the bird 2 hours.
Since the bird was travelling at 120 kilometers per hour, then in 2 hours the bird will travel
2 x 120 since DISTANCE = SPEED X TIMES AND 2 X120 = 240 KILOMETERS. ANSWER
Date: 2023-11-15
Related videos
Comments and reviews: 27
Bharat
This can also be solved by taking time of travel of Train A, Train B and the bird as equal, by taking distance travelled by Train A as variable 'x'. There by distance travelled by Train B will be '300-x'. Then time of travel by Train A and Train B respectively will be:
'60/x' and '90/(300-x)'
But as earlier said the time of travel is equal for all the three.
Solving the above we get time as 2 hrs.
Taking this, distance travelled by the bird will be 2-120= 240 kms
reply
This can also be solved by taking time of travel of Train A, Train B and the bird as equal, by taking distance travelled by Train A as variable 'x'. There by distance travelled by Train B will be '300-x'. Then time of travel by Train A and Train B respectively will be:
'60/x' and '90/(300-x)'
But as earlier said the time of travel is equal for all the three.
Solving the above we get time as 2 hrs.
Taking this, distance travelled by the bird will be 2-120= 240 kms
reply
Steve
There is a story about John von Neuman involving a similar puzzle about two cyclists and a fly. The hostess at a dinner party Von Neuman was attending asked Von Neuman to solve it and he gave the correct answer after a second or two of thought. The hostess said she was disappointed that Von Neuman spotted the easy solution. -Many people try to sum the infinite series in their heads-, she said. Von Neuman looked surprised. -That's how I did it-, he said.
reply
There is a story about John von Neuman involving a similar puzzle about two cyclists and a fly. The hostess at a dinner party Von Neuman was attending asked Von Neuman to solve it and he gave the correct answer after a second or two of thought. The hostess said she was disappointed that Von Neuman spotted the easy solution. -Many people try to sum the infinite series in their heads-, she said. Von Neuman looked surprised. -That's how I did it-, he said.
reply
Roxa
Hello! Sir can u make if you like, then post one more question of this type, I, actually do not know how to post
A merchant has 3camels, wants to cross a 1500 km wide desert, the camel can carry 1000ltrs of water but they need 1ltr/km movement, how the merchant should manage to cross the desert, and no any camel should die short of water in the desert.
reply
Hello! Sir can u make if you like, then post one more question of this type, I, actually do not know how to post
A merchant has 3camels, wants to cross a 1500 km wide desert, the camel can carry 1000ltrs of water but they need 1ltr/km movement, how the merchant should manage to cross the desert, and no any camel should die short of water in the desert.
reply
Sarthak
I think the distance is 184. 24 km because the bird is moving back and forth and till it collide.
When bird reach train B it covers 171. 4 km.
When bird reverses it direction and meet train A it covers 57. 12.
When it again starts from train A it covers 5. 72 km and collision happens.
Hope you understand
reply
I think the distance is 184. 24 km because the bird is moving back and forth and till it collide.
When bird reach train B it covers 171. 4 km.
When bird reverses it direction and meet train A it covers 57. 12.
When it again starts from train A it covers 5. 72 km and collision happens.
Hope you understand
reply
burke
I got 240 to, but acctually its less than that if we calculate bird and train inertia (slowing down and accelerating again for bird and accelerating for trains. If accelerating at constant rates and bird and trains need 10 seconds to get to full speed, then bird will will fly little over 148 km.
reply
I got 240 to, but acctually its less than that if we calculate bird and train inertia (slowing down and accelerating again for bird and accelerating for trains. If accelerating at constant rates and bird and trains need 10 seconds to get to full speed, then bird will will fly little over 148 km.
reply
---------
At the end of the 2nd hour, train A would have travelled 120km while B travelled 180 km. Since total distance is 300 km, the trains will crash at the end of the 2nd hour. Our bird is will also be flying 2 hours before the collision at the speed of 120 km/hr. Hence 240km
reply
At the end of the 2nd hour, train A would have travelled 120km while B travelled 180 km. Since total distance is 300 km, the trains will crash at the end of the 2nd hour. Our bird is will also be flying 2 hours before the collision at the speed of 120 km/hr. Hence 240km
reply
Ayush
240 kms? Am I right. dude it's easy just calculate the time taken by two trains to collide. just forget about the turning of bird. just thought it as bird keeps moving at 120 kmph for the time taken by trains to collide. easy
. lol u got the same trick. damn am smart lol
reply
240 kms? Am I right. dude it's easy just calculate the time taken by two trains to collide. just forget about the turning of bird. just thought it as bird keeps moving at 120 kmph for the time taken by trains to collide. easy
. lol u got the same trick. damn am smart lol
reply
Devon
ANOTHER WAY TO FIND THE TIME BOTH TRAIN TRAVELS IS TO ADD UP THEIR SPEED SINCE WERE MOVING TOWARDS EACH OTHER. SO 90 +60 = 150 Km/hr
time it took to 'collide' (reach each other actually) = 300/ 150 = 2 hr, bird speed 120 km/ hr so bird distance 120 x 2 = 240 kilometers
reply
ANOTHER WAY TO FIND THE TIME BOTH TRAIN TRAVELS IS TO ADD UP THEIR SPEED SINCE WERE MOVING TOWARDS EACH OTHER. SO 90 +60 = 150 Km/hr
time it took to 'collide' (reach each other actually) = 300/ 150 = 2 hr, bird speed 120 km/ hr so bird distance 120 x 2 = 240 kilometers
reply
SIVNAND
Thank u bro
I was looking for this kind of answer for this type of question you did a great job. All others make us understand things theoretically but you made this way easier by animating it.
I appreciate the work done by u. Thank u for helping me
reply
Thank u bro
I was looking for this kind of answer for this type of question you did a great job. All others make us understand things theoretically but you made this way easier by animating it.
I appreciate the work done by u. Thank u for helping me
reply
Deepak
Actually this wasn't a problem for maths lovers. The moment you said that the two train travel towards each other at different speeds, I knew that it could be solved really easily by considering their relative speeds.
reply
Actually this wasn't a problem for maths lovers. The moment you said that the two train travel towards each other at different speeds, I knew that it could be solved really easily by considering their relative speeds.
reply
Dougal
The trains never collide.
Instead, train A, train B, city A, and city B are all destroyed in the explosion caused by the infinitely fast oscillation of the bird just before 2 hours after the trains and bird start.
reply
The trains never collide.
Instead, train A, train B, city A, and city B are all destroyed in the explosion caused by the infinitely fast oscillation of the bird just before 2 hours after the trains and bird start.
reply
omkar
Sir, think logically after two hours 1st train will travel 120 km and the 2nd train will travel 180km then how is it possible? That they collide, even if they are 60km away from each other?
reply
Sir, think logically after two hours 1st train will travel 120 km and the 2nd train will travel 180km then how is it possible? That they collide, even if they are 60km away from each other?
reply
Vidhya
I did it in a different method. I just wanted to know when the Train A gets collided. Train A takes 120km to get collided for which it takes 2 hours. Then, bird's fast x hour = 240km
reply
I did it in a different method. I just wanted to know when the Train A gets collided. Train A takes 120km to get collided for which it takes 2 hours. Then, bird's fast x hour = 240km
reply
Sreekanth
Could you please do a video with question - number of trips by the bird before collision -?
You have answered that in this video but the way to prove will be interesting.
reply
Could you please do a video with question - number of trips by the bird before collision -?
You have answered that in this video but the way to prove will be interesting.
reply
The
BRUH.
DO U EVEN KNOW HOW TO RE-ARANGE FORMULAS?
Speed=distance over time so.
Time=speed multiplied by distance
AND NOT DIVIDE!
reply
BRUH.
DO U EVEN KNOW HOW TO RE-ARANGE FORMULAS?
Speed=distance over time so.
Time=speed multiplied by distance
AND NOT DIVIDE!
reply
Abinesh
You can explain it in more simple way. it seems too inconvenient to understand but their is an easier way than this to find the distance
reply
You can explain it in more simple way. it seems too inconvenient to understand but their is an easier way than this to find the distance
reply
Adi
I made a geometric series and spent my 20 minutes. When I saw the solution I broke my computer. Now I have to comment this by my Smartphone.
reply
I made a geometric series and spent my 20 minutes. When I saw the solution I broke my computer. Now I have to comment this by my Smartphone.
reply
jonniboye
Went through the first iteration of the infinite series before I realized how silly I was being and solved it using relative speeds.
reply
Went through the first iteration of the infinite series before I realized how silly I was being and solved it using relative speeds.
reply
Shashank
Thought of some calculations but that was too easy. I missed the fact that no matter how bird flies, distance will be same
reply
Thought of some calculations but that was too easy. I missed the fact that no matter how bird flies, distance will be same
reply
Sharuh
Idk man I liked my solution to a fundamentally flawed riddle. As if it's not the solution it's not a riddle it's basic math
reply
Idk man I liked my solution to a fundamentally flawed riddle. As if it's not the solution it's not a riddle it's basic math
reply
RT
I am preparing for jee and i got the same question in my book but their we have to calculate the no. Of times the turned ---
reply
I am preparing for jee and i got the same question in my book but their we have to calculate the no. Of times the turned ---
reply
Animesh
I would like to know what is the distance travelled by the bird in forward direction and backward direction separately.
reply
I would like to know what is the distance travelled by the bird in forward direction and backward direction separately.
reply
Ayush
How can we find the total distance travelled by the bird before it reaches the second train for the second time?
reply
How can we find the total distance travelled by the bird before it reaches the second train for the second time?
reply
Chris
The bird doesn't fly at a constant 120 Km. It has to slow and stop for a moment every time it changes direction.
reply
The bird doesn't fly at a constant 120 Km. It has to slow and stop for a moment every time it changes direction.
reply
sMyles
The real question is how can I use the bird to travel between cities since it flies faster than the faster train.
reply
The real question is how can I use the bird to travel between cities since it flies faster than the faster train.
reply
hitesh
I got this one right ammar good job your riddles are very trick they are great excersise for brain thanks
reply
I got this one right ammar good job your riddles are very trick they are great excersise for brain thanks
reply
Rahul
All Indian science students should recognise this problem from ncert physics book from 11th standard.
reply
All Indian science students should recognise this problem from ncert physics book from 11th standard.
reply
Add a review, comment
Other channel videos
