Number of apples bought = 7 and Number of kiwis bought = 2
Solution:
Let "k" be the number of kiwi bought
Let "a" be the number of apples bought
At a market, a kiwi costs $1, and an apple costs $1.50
Cost of each kiwi = $ 1
Cost of each apple = $ 1.50
If Charlie bought 5 more apples than kiwis and spent $12.50
Apples bought = 5 + kiwis
a = 5 + k --------- eqn 1
Also he spent $ 12.50
Number of apples bought x Cost of each apple + number of kiwi bought x Cost of each kiwi = 12.50

1.5a + k = 12.50 --------- eqn 2
Let us solve eqn 1 and eqn 2 to find values of "a" and "k"
Substitute eqn 1 in eqn 2
1.5(5 + k) + k = 12.5
7.5 + 1.5k + k = 12.5
7.5 + 2.5k = 12.5
2.5k = 5
k = 2
Therefore from eqn 1,
a = 5 + k = 5 + 2 = 7
a = 7
Summarizing the results:
Number of apples bought = 7
Number of kiwis bought = 2