word problem

[dlthompson81]

The average salary for computer programmers is $7,740 less than twice the average salary for carpenters. Combined, their average salary are $99,000. Determine the average salary for each of these jobs.

I was able to come up with this:
Computer Programmer Salary 2y - 7740 = x
Carpenter Salary 99000 - x = y

I got the answer from the back of the book:
Computer Programmer Salary $63,420
Carpenter Salary $35,580

The numbers come out correct when i plug them into my equation, but I can't figure out how to come up with those two numbers. I tried to work it out on my own for a few hours, but I couldn't get it. Thanks in advance for the help.

 

[arthur ohlsten]

P = programmers salary(P)
C=carpenters salary(C)

P=2C-7740
[P+C]=99000

P+C=99000
P=99000-C substitute

99000-C=2C-7740
106740=3c
C=35580 answer

Arthur

 

[Mrspi]

If you give a man a fish (or an answer!) he eats for a day (or, he passes for that day's homework).

If you TEACH a man to fish (or how to solve a problem), he'll eat for a lifetime...or, he MAY be able to do future problems on his/her own.