SOLUTION: 3.) A father can take 3 hours to mow the lawn. If the son takes 4.5 hours to mow the same lawn, at what time will they finish mowing the lawn together after starting at 7:30 pm?
Algebra ->
Percentage-and-ratio-word-problems
-> SOLUTION: 3.) A father can take 3 hours to mow the lawn. If the son takes 4.5 hours to mow the same lawn, at what time will they finish mowing the lawn together after starting at 7:30 pm?
Log On
Question 890099: 3.) A father can take 3 hours to mow the lawn. If the son takes 4.5 hours to mow the same lawn, at what time will they finish mowing the lawn together after starting at 7:30 pm? Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! 3.) A father can take 3 hours to mow the lawn. If the son takes 4.5 hours to mow the same lawn, at what time will they finish mowing the lawn together after starting at 7:30 pm?
Let x = time it takes for both
then
x(1/3 + 1/4.5) = 1
x(4.5 + 3) = (3)(4.5)
x(7.5) = 13.5
x = 13.5/7.5
x = 1.8 hours
or
x = 1 hour and 48 minutes
.
time at completion:
7:30 + 1:48 = 9:18 pm
