Question

Bus A stops at a certain bus stop every 25 minutes. Bus B stops at the same stop every 40 minutes. If both buses are at the bus stop at 9:30 a.m., when is the next time they will be there together again? A. 12:20 p.m. B. 12:50 p.m. C. 1:10 p.m. D. 1:30 p.m.​

Answer 1

Basically we are finding the least common multiple of 40 & 25:

25 : 1,25,50,75,100,125,150,175,200

40: 1,40,80,120,160,200

They will meet again after 200 minutes.

$x = \frac{200}{60} = 3 + \frac{20}{60}$

So they will meet again after 3 hours and 20 minutes;

9:30 + 3:20 = 12:50 p.m.

That's your answer