Make two equations
O = orange, A = allele
(12O + 7A = 5.36) 2
(8O + 5A = 3.68) 3
Make one of them same coefficient
24O + 14A = 10.72
24O + 15A = 11.04
Subtract both equations
-1A = -0.32
A = 0.32
24O + 14(0.32) = 10.72
24O + 4.48 = 10.72
24O = 6.24, O = 0.26
Solution:
One apple = $0.32
One orange = $0.26