SOLUTION: Helping my child do her math and could use some help. Twin brothers, person A and person B, can mow their grandparents lawn together in 42 minutes. Person A could mow the lawn b

Algebra.Com
Question 863009: Helping my child do her math and could use some help.
Twin brothers, person A and person B, can mow their grandparents lawn together in 42 minutes. Person A could mow the lawn by himself in 13 minutes less time than person B. How long does it take each person to mow the lawn by himself.
Many thanks in advance,
Found 2 solutions by ewatrrr, richwmiller:
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!


Hi

The Set-Up concept is how much Lawn per minute:

    A  + B = together

   Multiplying thru by 42x(x-13) so as all denominators = 1

   42x + 42(x-13) = x(x-13)

   84x - 546 = x^2 - 13x

  x^2 -97x + 546 = 0







      x =  182/2 = 91min    |Note must be more than 42, root of 6 is Extraneous

B takes  

and..

 1/78 + 1/91 = 1/42 

Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!
 1/B+1/(B-13)=1/42

A=B-13

B=91 

A=78



 

RELATED QUESTIONS


Twin brothers, person A and person B, can mow their grandparents lawn together in 42... (answered by ankor@dixie-net.com)

twin brothers person a and person b, can mow their grandparents lawn together in 20... (answered by ewatrrr)

I am helping my daughter do her homework and we are stuck on this one. Please help me... (answered by mananth,josgarithmetic)

Twin brothers, person A and person B can mow their parents lawn together in 72 minutes.... (answered by lwsshak3)

Twin brothers, Andy and Brian, can mow their grandparents lawn together in 40 min. Brian... (answered by richwmiller)

Twin Brothers,andy and brian can mow their grandparents lawn together in 18 minutes.... (answered by solver91311)

Twin brothers, Billy and Bobby, can mow their grandparents lawn together in 89 minutes.... (answered by ad_alta)

Twin brothers andy and brian can mow their granfathers lawn together in 40 minutes. Brian  (answered by ikleyn)

twin brothers, andy and brian, can mow their grandparents lawn together in 30 minutes.... (answered by josgarithmetic)