# Moderate Time and Work Solved QuestionAptitude Discussion

 Q. A red light flashes 3 times per minute and a green light flashes 5 times in two minutes at regular intervals. If both lights start flashing at the same time, how many times do they flash together in each hour?
 ✔ A. 30 ✖ B. 29 ✖ C. 31 ✖ D. 32

Solution:
Option(A) is correct

Red light flashes every 20 seconds

Green light flashes every 24 seconds

Therefore, they will flash together every 120 seconds

In every hour, they will flash = $\dfrac{3600}{120}=30$ times

Edit: Thank you, Dan, for notifying the typo, corrected it.

## (4) Comment(s)

Harshit Varshney
()

Red light - 3 times--1 min

6times --2min

green light- 5 times--2min

red light -150 times-- 60 min

green light -180 times-- 60 min

now take the HCF (150,180)=30

Sm Mudabbir
()

red light will flash 6 times in 2 minutes and green flash 5 time in 2 min their lcm is 30 that is it

Dan
()

Please correct the answer . It will be unitless as it is asked how many times lights will flash in 1 hour.

Deepak
()

Thank you, Dan, for notifying, corrected it.