Let the cherry pies be c and the pumpkin pies be p:
Shawna: c + 3p = 55
Amanda: 3c + 3p = 69
We want to find the cost of c + p. To do this, the easiest way is to divide the second equation by 3:
(3c + 3p)/3 = 69/3
c + p = 23
Therefore, 1 cherry pie & 1 pumpkin pie cost $23.