Question 158201
S+L=12 OR S=12-L
60S+180L=1,200
SUBSTITUTING (12-L) FOR S IN THE SECOND EQUATION WE GET:
60(12-L)+180L=1,200
720-60L+180L=1,200
120L=1,200-720
120L=480
L=480/120
L=4 LARGE PAINTING SOLD.
S=4=12
S=12-4
S=8 SMALL PAINTINGS SOLD.
PROOF:
60*8+4*180=1,200
480+720=1,200
1,200=1,200