SOLUTION: Help me solve this. Kevin takes 40mins to mow his lawn alone. But when Jose and Kevin mow the lawn together it takes 15mins. How long will it take Jose to mow the lawn by himself.

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Help me solve this. Kevin takes 40mins to mow his lawn alone. But when Jose and Kevin mow the lawn together it takes 15mins. How long will it take Jose to mow the lawn by himself.      Log On


   

Question 891221: Help me solve this.
Kevin takes 40mins to mow his lawn alone. But when Jose and Kevin mow the lawn together it takes 15mins. How long will it take Jose to mow the lawn by himself.
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
This only involves uniform rates of the two people. Use the rate as LAWNS per MINUTE.

Kevin, 1/40
Jose, you do not know his rate, say 1/t
Kevin&Jose, 1/15

Their combination rate is the sum of their individual rates.
highlight_green%281%2F40%2B1%2Ft=1%2F15%29
Denominators are 2%2A2%2A2%2A5, t, 3%2A5;
LCD is 8%2A3%2A5%2At;
Solve for t.



(multiply the left and right sides by L.C.D. to begin simplifying before finish solving for t.)