Aakruthi and Prakruthi are playing skipping-rope. Aakruthi skips 30 times in a minute and Prakruthi skips 20 times in a minute. Both of them start skiping at 4.50 p.m. and continue till 5 p.m. without any interruption. How many times do they skip the rope simultaneously after 4.50 p.m. ?

Answer

100

Explanation

Time taken by Aakruthi to skip the rope for 1 time `=(60)/(30)=2` seconds.
Time taken by Prakruthi to skip the rope for 1 time
`=(60)/(30)=3` seconds
`:.` Time taken by them to skip the rope simultaneously
`=LCM(2,3)=6` second
`:.` For every 6 seconds, they skip the rope simultaneously.
`implies` They skip the rope 10 times for every minutes.
`:.` In the given time, i.e. , 10 minutes, they skip the rope simultaneously`=10xx10=100` times.