Question

Five bells first begin to toll together and then at
intervals of 3, 5, 7, 8 and 10 s. Find after what interval
they will again toll gether. How many times do they
toll together in one hour?
(a) 14 min; 3 times
(b) 12 min; 4 times
(c) 14 min; 4 times
(d) 12 min; 3 times

Answer 1

Step-by-step explanation:

4.66 Minutes, 3 Minutes, 3.5 Minutes, 4 Minutes

Answer 2

Step-by-step explanation:

Time interval = LCM of 3,5,7,8,10

= 2³×3×5×7

= 840/60 (Since, 1 minute = 60 seconds)

= 14 minutes

So after every 14 minutes the bells will toll together.

Therefore, no. of times they will toll together in 1 hour = 60/14 = 4 times (Since, 1 hour = 60 minutes)

Hence, option c is the correct answer.