Question

three Bells toll at intervals of 36 seconds 40 seconds and 48 seconds respectively they start ringing together at a particular time they next toll together after ?
Pls answer tomorrow is my final exam

Answer 1

Take out their LCM

LCM by Prime Factorisation =

2 | 36, 40, 48
2 | 18, 20, 24
2 | 9, 10, 12
2 | 9, 5, 6
3 | 9, 5, 3
3 | 3, 5, 1
5 | 1, 5, 1
| 1, 1, 1

=> LCM = 2 × 2 × 2 × 2 × 3 × 3 × 5

= 720
=> They will toll together after 720 seconds

=> Convert to minutes 720/60

=> 13 minutes

Answer 2

⇔ LCM of 36 , 40 and 48 :-

⇆ LCM = 2 × 2 × 2 × 2 × 3 × 3 × 5

= 720

⇒ Toll together = 720 sec

⇒Convert sec to min :-

= $\frac{720}{60}$

= 13 min