SOLUTION: Sam can mow a lawn in 80 minutes. Bullwinkle can mow the same lawn in 120 minutes. How long does it take for both Sam and Bullwinkle to mow the lawn if they are working together? E

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Sam can mow a lawn in 80 minutes. Bullwinkle can mow the same lawn in 120 minutes. How long does it take for both Sam and Bullwinkle to mow the lawn if they are working together? E      Log On


   

Question 1147776: Sam can mow a lawn in 80 minutes. Bullwinkle can mow the same lawn in 120 minutes. How long does it take for both Sam and Bullwinkle to mow the lawn if they are working together? Express your answer as a reduced fraction
Found 2 solutions by ankor@dixie-net.com, Alan3354:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Sam can mow a lawn in 80 minutes.
Bullwinkle can mow the same lawn in 120 minutes.
How long does it take for both Sam and Bullwinkle to mow the lawn if they are working together?
Express your answer as a reduced fraction
:
Assuming they have two lawn mowers
let t = time when working together
let the completed job = 1
Each will do a fraction of the job. the two fractions add up to 1
t%2F80 + t%2F120 = 1
multiply by 240, to get rid of the fractions
240*t%2F80 + 240*t%2F120 = 240(1)
Cancel the fractions
3t + 2t = 240
5t = 240
t = 240/5
t = 48 minutes when working together
:
:
Check this out
48%2F80 + 48%2F120 = 1
6%2F10 + 4%2F10 = 1

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Sam can mow a lawn in 80 minutes. Bullwinkle can mow the same lawn in 120 minutes. How long does it take for both Sam and Bullwinkle to mow the lawn if they are working together? Express your answer as a reduced fraction
=================
80*120/(80+120) = 9600/200 = 48 minutes