Six bell commence tolling together and toll at intervals of 5, 10, 15, 20, and 30 s, respectively. In 60 min, how many times do they toll together?

Six bell commence tolling together and toll at intervals of 5, 10, 15,

1.	Six bell commence tolling together and toll at intervals of 5, 10, 15, 20, and 30 s, respectively. In 60 min, how many times do they toll together?
A.	20
B.	15
C.	13
D.	11
Answer» D. 11