[sexyrexy88]

A jazz concert brought in $124,000 on the sale of 7,900 tickets. If tickets sold for $10 and $20 each, how many of each type of tickets were sold?

[PAPPAGEORGIO]

This problem gives you two unknowns (Two different types of tickets). That means you will need at least two equations.
Lets say the $10.00 ticket is named "x" and the $20.00 ticket is named "y". Your two equations would be as follows...

$10.00x + $20.00y = $124,000 eqn 1

x + y = 7,900 tickets eqn 2

solve for either x or y in one of the equations. I use eqn 2 because it looks more simple.

x = 7900 - y eqn 3

now "plug" eqn 3 into eqn 1

$10.00 (7900 - y) + 20.00y = 124000 eqn 4

if you factor this out you are left with

79000 - 10y + 20y = 124000 eqn 5

From here just get y by itself. Once you have y you can plug it into eqn 2 and you will have your answer. I hope I set it up enough for you to figure out. Give it a shot and let me know if you are still stuck.