Let x = price for each cake and y = price of each pie in dollars.

We can get two equations out of the data. One from the Friday set, the other from the Saturday set.

Equation  1: 30x+20y=460

Equation  2: 30x+40y=620

Then, we subtract both equations. The difference would be:

-20y = -160
y = -160 ÷ -20
y = $8

Finally, we substitute y to any of the equations. Suppose, we use equation 1:

30x + 20(8) = 460
30x = 460 – 160
30x = 300
x = 300 ÷ 30 
x = $10

Therefore, the cost for each cake and pie is $10 and $8, respectively.