Question

Maths
Chapter-1 real numbers
ques 1- Four different electronic devices make a beep after every 30 minutes , 1 hours , 1 hours 30 minutes and 1 hours 45 minutes respectively. All the device beeped together at 12 noon. when will they beep again together at.​
Please Help me

Answer 1

Answer:

Next they will beeped together at 9a.m.

Step-by-step explanation:

First device beeps in every 30 min

Second device beeps in every 60 min

Third device beeps in every 90 min

Fourth device beeps in every 105 min

That means together they beep after how many minutes

We calculate LCM (30, 60, 90, 105)

30 = 2 x 3 x 5

60 2 x 2 x 3 x 5

90 = 2 x 3 x 3 x 5

105 = 3 x 5 x 7

So, LCM 2² x 3² x 5 x 7 = 1260

-> ie, in 1260/60 = 21 hrs they beep together.

All beeped together after 12 noon at 21 hrs later. i.e, (12 +21)hrs = 9a.m.

ANSWER - Next they will beeped together at 9a.m.