SOLUTION: Jack usually mows his lawn in 3 hours. Marilyn can mow the same yard in 7 hours. How much time would it take for them to mow the lawn together?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Jack usually mows his lawn in 3 hours. Marilyn can mow the same yard in 7 hours. How much time would it take for them to mow the lawn together?      Log On


   

Question 395319: Jack usually mows his lawn in 3 hours. Marilyn can mow the same yard in 7 hours. How much time would it take for them to mow the lawn together?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Let x represent time to mow the lawn together

Question states***per hour being the equalizer

 1/3 + 1/7 = 1/x  |Multiplying each term by 21x so as alll denominators=1

 7x + 3x = 21

     10x = 21 hr 

       x = 2.1 hr