Question

ram takes 20 minutes to inspect a car, while robert takes only 18 minutes.if both start inspecting car at 8.00 hours what is the first time at which both will have finished inspecting a car at the same point time

Answer 1

you must take the lcm of both of them
it's 180
so at 11.00 hours both of them will have finished inspecting the car at same point time

Answer 2

at 11oclock they will finish it by finding the pcm of 20 and 18 which is 180 that is equal to 3 hours which we have to add to 8 that is 11