y=a/4 x(x属于正整数)
设新价为b,则售价为b(1-20%)
.∵原价为a,∴进价为a(1-25%).
∴b(1-20%)-a(1-25%)=b(1-20%)·25%,得b=.
∴y=b×20%×x=5/4 a×20%.∴y=a/4 x (x属于正整数).
y=a/4 x(x属于正整数)
设新价为b,则售价为b(1-20%)
.∵原价为a,∴进价为a(1-25%).
∴b(1-20%)-a(1-25%)=b(1-20%)·25%,得b=.
∴y=b×20%×x=5/4 a×20%.∴y=a/4 x (x属于正整数).