Answer:
6 shirts (with 1 jacket and $5 left)
Step-by-step explanation:
Since he's already committed to the jacket, the $18 for that is already gone, so of the $95 he came with, $95 - $18 = $77 remains for shirts. He can buy as many $12 shirts as 'fit' in $77, i.e. the quotient of $77 / $12 = Q 6 R 5, i.e. 6 shirts at $12 each for 6 * 12 = $72 in shirts with $5 left over