You have

apples left.
You have 5 whole apples, you took one whole apple out, which equals 4 whole apples left. Then with the whole apple you took out, you ate

of it.
Jack ate
of an apple in 5 apples. If you say that Jack ate

of 3 apples, then he ate

apples. So there isn't any difference when he ate

of an apple.
Your answer would be $11.50 I hope this helps you out! :)
compare the triangles ΔABC and ΔBCD
∡ABC = ∡BCD (given)
AB = CD (given)
BC = BC (common) } = > (SAS) ΔABC ≡ ΔBCD = > AC = BD