Algebra
posted by Bob .
Mountainside Fleece sold 40 neckwarmers. Solidcolor neckwarmers sold for $9,90 each and print ones sold for $12,75 each. In all, $421,65 was taken in for the neckwarmers. How many of each type were sold?

You know the following:
S+P=40
9.9*S + 12.4*P=421.65