X, y, z starts at the same time in the same direction to run around a ...
Problem:
X, y, z starts at the same time in the same direction to run around a circular stadium x complete a round in 126 seconds, y in 154 seconds and z in 231 seconds. After what time they meet again at the starting point and how many rounds would have x, y, z complete by this time? Explain in details.
Solution:
Let's assume that they meet after t seconds and in that time they complete n rounds.
Calculating the speed of each person:
Speed of x = Distance/Time = 1/126
Speed of y = Distance/Time = 1/154
Speed of z = Distance/Time = 1/231
Calculating the distance of the round:
As they complete full rounds, the distance covered by each person is equal to the circumference of the stadium.
Circumference of the stadium = 2πR, where R is the radius of the stadium.
Let's assume the radius of the stadium to be 'r'.
Circumference of the stadium = 2πr
Distance covered by x in one round = 2πr
Distance covered by y in one round = 2πr
Distance covered by z in one round = 2πr
Calculating the number of rounds:
As each person completes 'n' rounds, we can say that:
Distance covered by x = n * 2πr
Distance covered by y = n * 2πr
Distance covered by z = n * 2πr
Calculating the time taken:
As each person completes 'n' rounds in 't' seconds, we can say that:
Time taken by x = n * 126 seconds
Time taken by y = n * 154 seconds
Time taken by z = n * 231 seconds
Calculating the value of 'n' and 't':
As they meet at the starting point after 't' seconds, we can say that:
Distance covered by x in 't' seconds = Distance covered by y in 't' seconds = Distance covered by z in 't' seconds
Therefore, we can say that:
n * 2πr = (n * 1/126) * t * 2πr = (n * 1/154) * t * 2πr = (n * 1/231) * t * 2πr
Cancelling out 2πr from both sides, we get:
n = (t/126) = (t/154) = (t/231)