SOLUTION: #16 LISA CAN SHOVEL SNOW FROM HER DRIVEWAY IN 65 MINUTES. bILL CAN DO THE DRIVEWAY IN 45 MINUTES. hOW LONG WOULD IT TAKE LISA AND BILL TO SHOVEL THE DRIVEWAY TOGETHER?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: #16 LISA CAN SHOVEL SNOW FROM HER DRIVEWAY IN 65 MINUTES. bILL CAN DO THE DRIVEWAY IN 45 MINUTES. hOW LONG WOULD IT TAKE LISA AND BILL TO SHOVEL THE DRIVEWAY TOGETHER?      Log On


   

Question 534142: #16
LISA CAN SHOVEL SNOW FROM HER DRIVEWAY IN 65 MINUTES. bILL CAN DO THE DRIVEWAY IN 45 MINUTES. hOW LONG WOULD IT TAKE LISA AND BILL TO SHOVEL THE DRIVEWAY TOGETHER?
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
Work problems like this are fraction problems.
Lisa does the whole job in 65 minutes, so she does 1/65 of the job per minute.
Bill does 1/45 of the job per minute.
.
(1/65+1/45)*x minutes = 1 whole job completed
.
(45+65)/(45*65) * x = 1
.
110/2925 * x = 1
.
22/585 * x = 1
.
22x = 585
.
x = 585/22
.
x = 26.590 min
.
Working together they can do the job in about 26.6 minutes.
.
Always check your work.
1/45 * 26.6 = .591 = amount of the job done by Bill
1/65 * 26.6 = .409 = amount of the job done by Lisa
Total = 1 whole job.
.
Done.