SOLUTION: You have a string of blinking lights. The blue lights blink every 5 seconds and the red lights blink every 3 seconds. How many times will the lights blink at the same time in one m

Question 1127797: You have a string of blinking lights. The blue lights blink every 5 seconds and the red lights blink every 3 seconds. How many times will the lights blink at the same time in one minute.
Found 2 solutions by addingup, MathTherapy:
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!

Numbers divisible by 5 are those ending in 5 and 0. Thus, they will blink together every time a multiple of 3 is 5 or 0:
:
3,6,9,12,(15),18,21,24,27,(30),33,36,39,42,(45), 48, 51, 54, 57, (60)
You can count the times, I put them in parenthesis.

Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

You have a string of blinking lights. The blue lights blink every 5 seconds and the red lights blink every 3 seconds. How many times will the lights blink at the same time in one minute.

LCM of 5 and 3, from its first, 15 to its last, 60!
List and count them!
RELATED QUESTIONS
The red lights in an advertisement board blink every 3 seconds. The blue lights blink... (answered by stanbon)
When Will The Lights blink. The Red light blinks every 4 seconds, the green lights blink... (answered by greenestamps,josgarithmetic)
Hi, there can someone help me.There is a string of yellow and pink lights on a window.... (answered by ikleyn)
Two neon lights are turned on at the same time. One blinks every 4 seconds and the other... (answered by Alan3354)
The green neon lights flash every 5 seconds, the blue every 6 seconds and the red every 7 (answered by Boreal)
A certain machine is composed of three led light blink in varied materials . the red... (answered by stanbon)
On a Christmas tree a first set of ligjts flashes every 3 seconds, a second set of lights (answered by ankor@dixie-net.com)
An observer on a boat on Port Phillip Bay at night can see see three different shore... (answered by oscargut)
Two smugglers, Bill Bogus and Sally Seadog, have set up signal lights that flash... (answered by Alan3354)