Answer:
So the next time they will leave together is 4:24 pm
Explanation:
Since both the buses left at 4 pm and red line bus leaves every 6minutes and blue line bus leaves every 8 minutes they next time they leave together can be found by taking the L.C. M of 6 and 8.
The L.C. M is found by multiplying all the factors and chosing one which common in both numbers.
Factors of 6 = 2*3
Factors of 8= 2*2*2
In these numbers 2 is common in both.The rest of the numbers( 2*2*3 )are multiplied with the the common 2 to get the L.C.M
L.C.M= 2*2*2*3= 24 minutes
So the next time they will leave together is 4:24 pm