Question

Rohan set his alarm at intervals of 10. minutes 15 minutes 30 minutes

Answer 1

Answer:

1 hour if it wrong then tell me in comments

Answer 2

All the alarm clocks will ring together after the number of minutes which are least common to all the three.

=> lcm (10, 15, 30) : 2×3×5 =30

So ,After 30 minutes all the three clocks will ring together.