A blue light every 30seconds. A red light blinks every 40seconds. If both lights blink at exactly 1:00pm, at what time will they blink at the same time again?

The least common multiple of 30 and 40 is 120.

30, 60, 90, 120

30, 80, 120

1:00 + 120 seconds = ?

To determine at what time the blue and red lights will blink at the same time again, we need to find the least common multiple (LCM) of the two time intervals at which the lights blink.

The blue light blinks every 30 seconds, which can be represented as 30s, and the red light blinks every 40 seconds, represented as 40s.

To find the LCM, we need to determine the smallest positive integer that is divisible by both 30 and 40.

Let's list the multiples of 30 and 40:
Multiples of 30: 30, 60, 90, 120, 150, ...
Multiples of 40: 40, 80, 120, 160, 200, ...

From the lists, we can see that the first common multiple of both numbers is 120.

Therefore, the blue and red lights will blink at the same time again after 120 seconds or 2 minutes.

To find the time at which the lights will blink simultaneously, we need to add the duration of 120 seconds to the initial time of 1:00 pm.

1:00 pm + 2 minutes = 1:02 pm

So, the blue and red lights will blink at the same time again at 1:02 pm.