4 bells first begin to toll together with an intervals of 5, 10, 15 & 20 sec.

4 bells first begin to toll together with an intervals of 5, 10, 15 & 20 sec. How many times does they toll together in an hr?

Quiz

Answer/Solution

60

Steps/Work

5|5, 10, 15, 20
2|1, 2, 3, 4
|1, 1, 3, 2
L.C.M of 5, 10, 15, 20 is 60
60 times
B