Problema Solution
Jeff takes 5hr longer to build a fence than it takes Bill. When they work together it takes them 6hr. How long would it take Bill to do the job alone?
Answer provided by our tutors
suppose bill take x hour
we get
1/x + 1/x+5 =1/6
x+x+5 / x^2 + 5x = 1/6
6(2x+5)=x^2+5x
x^2 + 5x - 12x - 30=0
x^2 - 7x - 30 = 0
(x-10)(x+3) = 0
x=10, x = -3
so x = 10
Bill take 10 hours
Jeff takes 15 hours