Question

A B and C start cycling around a circular path in the same direction at the same time circumference of the path is 1980 if the speed of a is 330 metre per minute and they start from some point then after what time they will be together at the starting point​

Answer 1

Answer:

Step-by-step explanation:

A will complete one round in 1980/330 = 6 min

B will complete one round in 1980/198 = 10 min

C will complete one round in 1980/220 = 9 min

Now, let A, B and C meet after time t and they would have respectively completed, n1, n2 and n3 rounds and they would be be x distance away from the start point

Hence, 330t = x + 1980n1

198t = x + 1980n2

220t = x + 1980n3

Substituting x from equation 1 into 2 and 3

198t = 330t - 1980n1 + 1980n2

1980(n1-n2) = 132t

t = 15(n1-n2)

Also,  220t = 330t - 1980n1 + 1980n3

1980(n1-n3) = 110t

Since t is same, and n1-n3 and n1-n2 can be any whole number, so we need to compute LCM of 15 and 18 which is 90

Hence, A,B and C will meet after 90 min.