At a local school dance, the booster club is having a fundraiser selling pictures. pictures without frames sell for $5, and with a frame sell for $10. they made $875 selling 100 pictures. how many of the had frames? show working

Let p = pictures only
let f = pictures with frames

p + f = 100
5p + 10f = 875

Solve for one variable in the first equation then plug into the second

p = 100 - f
5(100 - f) + 10f = 875
500 - 5f + 10f = 875
500 + 5f = 875
5f = 375
f = 75

75 pictures with frames were sold