Question

In one week, a music store sold 9 guitars for a total of $3611. Electric guitars sold for $479 each and acoustic guitars sold for $339 each. How many of each type of guitar were sold?

Answer 1

Let:
Electric=E
Acoustic=A

`A+E=9`
`A*339+E*479=3611`

`A=9-E` substitute in the second equation to get:
`(9-E)*339+E*479=3611`
`E=560/140=4`
So that:
`A=9-4=5`