SOLUTION: Peter takes 15 minutes longer to mow the lawn by himself than charles dows. Together they mow the lawn in 18 minutes. How long does it take for charles to mow the lawn by himselves
Algebra.Com
Question 101041: Peter takes 15 minutes longer to mow the lawn by himself than charles dows. Together they mow the lawn in 18 minutes. How long does it take for charles to mow the lawn by himselves?
I am having trouble figruing out the equasion of this problem.
I DO KNOW THIS:
p= c+15
c+p=18
p=c+15
c+p=18
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Peter takes 15 minutes longer to mow the lawn by himself than charles dows. Together they mow the lawn in 18 minutes. How long does it take for charles to mow the lawn by himself?
------------------------
Charles DATA:
time = x minutes/job ; rate = 1/x job/min
---------------
Peter DATA;
time = x+15 min/job ; rate = 1/(x+15) job/min
-----------------
Together DATA:
time = 18 min/j job ; rate = 1/18 job/min
------------------
EQUATION:
rate + rate = together rate
1/x + 1/(x+15) = 1/18
Multiply thru by 18x(x+15)
18(x+15) + 18x = x(x+18)
18x+18*15 + 18x = x^2 + 18x
x^2 -18x -270 = 0
x = [18 +- sqrt(18^2-4*-270)]/2
x = [18 +- 37.47]/2
Positive answer:
x = 27.735 minutes (time for Charles to do the job)
x+15 = 42.735 (time for Peter to do the job)
===========
Cheers,
Stan H.
RELATED QUESTIONS
It takes Peter 15 minutes longer than Charles to mow the lawn by himself. Together, they (answered by ankor@dixie-net.com)
It takes a boy 15 minutes longer to mow a lawn than it takes his sister. If they work... (answered by nerdybill)
It takes George 1 hour longer to mow the lawn than it takes Henry. Working together,... (answered by palanisamy)
It takes George 1 hour longer to mow the lawn than it takes Henry. Working together,... (answered by ankor@dixie-net.com)
It takes George 1 hour longer to mow the lawn than it takes Henry. Working together,... (answered by checkley77,CharlesG2)
It takes George 1 hour longer to mow the lawn than it takes Henry. Working together,... (answered by ankor@dixie-net.com)
twin brothers, andy and brian, can mow their grandparents lawn together in 30 minutes.... (answered by josgarithmetic)
By himself, a person can mow his lawn in 60 minutes. If his daughter helps, (answered by fractalier,Boreal)
Peter can mow a lawn in 40 minutes. John can mow the same lawn in 60 minutes. How long... (answered by ikleyn,josgarithmetic,math_tutor2020,greenestamps)