SOLUTION: Al makes $30 an hour. Bill makes $20 an hour. Bill joins Al on the job four hours after Al started. They finish the job, and the total cost for labor comes to $470. How many hours

Question 157043: Al makes $30 an hour. Bill makes $20 an hour. Bill joins Al on the job four hours after Al started. They finish the job, and the total cost for labor comes to $470. How many hours did each work?
By trial and error, I know that the number of hours is 11 for Al and 7 for Bill. I just need to show the work.
Al - 11 hours @ $30/hour = 330
Bill - 7 hours @ $20/hour = 140
Total = 470
Here is the equation that I came up with for figuring the number of hours each worked - where X=Al's hours and X-4 = Bill's hours. I'm fairly certain this equation is correct.
$470 = 30X + 20(x-4)
It's at this point that I get stuck. Any help would be greatly appreciated!
Found 2 solutions by jojo14344, alan22153:
Answer by jojo14344(1512) (Show Source):
You can put this solution on YOUR website!
Your on the ball amigo but a little bit of refinishing to do there.
Okay, let = no. of hours they work
But you see, Al is already ahead of 4 hours, so total no. of hours for him is right? Then putting everything into equation:
Al= plus
Bill= equals
Total=$470

--->
---------------> no. of hours Bill worked
--------> no. of hours Al worked
In doubt? let's check;
Al+Bill=$470

Thank you,
Jojo

Answer by alan22153(1) (Show Source):
You can put this solution on YOUR website!
470= 30X+20(x-4)
20*x=20X, and
20*-4=-80
470=30X+20X-80 or
add 80 to each side of the equation
550=50X
x=11 Al
x-4= 7 Bill