Question

Three bells in the church toll at intervals of 15, 18,45 sec respectively. After how many sec will the three bells toll together

Answer 1

at 90 seconds three bells toll together.
because lcm of given sec is 90

Answer 2

the three bells will toll together after 1 minute 30 seconds that is 90 seconds. because lcm of 15,q8 and 45 is 90.