SOLUTION: john takes 3hours longer than andrew to peel 400 pounds of apples. if together they can peel 400pounds of apples in 8hours then how long would it take john if he is working alone.

Algebra ->  Rate-of-work-word-problems -> SOLUTION: john takes 3hours longer than andrew to peel 400 pounds of apples. if together they can peel 400pounds of apples in 8hours then how long would it take john if he is working alone.      Log On


   

Question 123968: john takes 3hours longer than andrew to peel 400 pounds of apples. if together they can peel 400pounds of apples in 8hours then how long would it take john if he is working alone. round answer to three decimal places
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
x(x+3)/[x+(x+3)]=8
(x^2+3x)/(2x+3)=8
x^2+3x=16x+24
x^2+3x-16x-24=0
x^2-13x-24=0
using the quadratic equation we get:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x=(13+-sqrt[-13^2-4*1*-24])/2*1
x=(13+-sqrt[169+96])/2
x=(13+-sqrt265)/2
x=(13+-16.279)/2
x=(13+16.279)/2
x=29.279/2
x=14.6395 hours for Andrew working alone to peel 400 pounds of apples.
proof:
14.6395*17.6395/(14.6395+17.6395)=8
258.233/32.279=8
8=8