Problema Solution
John takes 3 hours longer than Andrew to peel 400 pounds of apples. If together they can peel 400 pounds of apples in 8 hours, then how long would it take John if he is working alone? (Please round your answer to three decimal places.)
Answer provided by our tutors
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=(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