Question

Two bells ring at every 7 minutes and 5 minutes respectively. If two bells ring together at 8:00 AM then the next time they will ring together at

• A. 08:35 AM
• B. 08:55 AM
• C. 08:07 AM
• D. 08:05 AM

Answer 1

The correct option is A 08:35 AM

We know that in muliplication table of 7 $\Rightarrow$ $7\times 5$ = 35
and in multiplication table of 5 $\Rightarrow$ $5\times 7$ = 35
Smallest number that can be divided evenly by both 7 and 5 is 35 or 35 is the Least Common Multiple of 7 and 5.
Given that bells ring together at 08:00 AM so after 35 minutes bells will ring together at 08:35 AM.