Andy and alex both decided to order prints of their photos. andy ordered 40 small 4x6 inch prints and 10 large 8x10 inch prints. he paid a total of $32.50 for his photos. alex paid 20$ for 20 small 4x6 inch prints and 8 large 8x10 inch prints. how much do the small and large sized prints cost

Let S and L represent the costs of small and large prints, respectively.
.. 40S +10L = 32.50 . . . . . . . . . Andy's order
.. 20S +8L = 20.00 . . . . . . . . .. Alex's order

Using Cramer's rule,
.. S = (10*20 -8*32.50)/(10*20 -8*40) = -60/-120 = 0.50
.. L = (32.50*20 -20.00*40)/-120 = -150/-120 = 1.25

Small prints cost $0.50.
Large prints cost $1.25.

She should use 12/3 to measure