First of I am impressed: I sell my handmade wooden bowls at craft shows. I wish I could see $1700 at such a show!
Anyway: Let S = # small paintings and L = the number of large ones
The S + L = 32
and 42S + 64L = 1762
S = 32 - L; substitute
42(32 - L) + 64L = 1762
1344 - 42L + 64L = 1726
22L = 418
L = 19
and
S = 13