Question

An electronic device makes a beep after every 60 sec. Another device makes a beep after 62 sec. They beeped together at 10 a.m. The time(in min) after which they will next make a beep together at earliest is-

Answer 1

Hint: In this question it is given that an electronic device makes a beep after every 60 sec. Another device makes a beep after 62 sec. They beeped together at 10 a.m. So we have to find the time after which they will next make a beep together at earliest. So in order to find the solution we have to find the Least Common Multiple(LCM) of 60 and 62, LCM will give us the time duration after which they make a beep together for the second time.
Complete step-by-step solution:
It is given that they beeped together at 10 a.m. First device makes a beep after 60 sec and the second device takes 62 sec in between each beep.

Since there is no common divisor of 30 and 31, so we can write LCM of 60 and 62,
LCM(60,62)=$2\times 30\times 31$=1860.
So we can say that they will make a beep together after 1860 sec,
Therefore, 1860 sec =$$\dfrac{1860}{60}$$ min=31 min.
So they will beeped together at (10.00+00.31)a.m=10.31 a.m
Which is our required solution.
Note: While solving this question you have to know that LCM any two numbers(e.g, a and b) gives you the least number which can be divisible by both the numbers(a and b) or we can say that after some repetition of the numbers(a and b), LCM will be the first number where they meet together.