Question 253119
an experienced plumber made $600 for working on a certain job.
 his apprentice, who makes $3 per hour less, also made $600. 
however, the apprentice worked 10 h more than the plumber. 
how much does the plumber make per hour?
:
Let x = amt per hour made by the plumber
then
(x-3) = amt made by the apprentice
:
Write a time equation: Time = {{{600/(hourly pay)}}}
:
Plumbers time = Appren time - 10 hrs
{{{600/x}}} = {{{600/((x-3))}}} - 10
Multiply equation by x(x-3); results
600(x-3) = 600x - 10x(x-3)
600x - 1800 = 600x - 10x^2 + 30x
:
Combine on the left to form a quadratic equation
10x^2 - 30x + 600x - 600x - 1800 = 0
10x^2 - 30x - 1800 = 0
:
simplify, divide by 10
x^2 - 3x - 180 = 0
Factors
(x - 15)(x + 12) = 0
positive solution
x = $15 per hr for the plumber
;
:
Check solution by finding the time of each
600/15 = 40 hrs
600/12 = 50 hrs, apprentice worked 10 hrs more