<u><em>20</em> palindromes exist that qualify this criteria rigorously</u>
Examples:
52025, 52125, 52225, 52325, 52425, 52525, 52625, 52725, 52825, 57975 etc.
Answer:
x=16
y=8.00
8/16=0.5 (50 cents per apple)
y=0.5x+0