At the patisserie, a single layer cake slice is $4 and a double layer cake slice is $7. Dusty buys 7 single layer cake slices and 5 double layer cake slices. If he pays with a $100 bill, how much change does he receive?
A step-by-step solution is:
37
Single layer cake slices cost $4 x 7 = $28.

Double layer cake slices cost $7 x 5 = $35.

All the cake slices together cost $28 + $35 = $63.

He will receive change of $100 - $63 = $37.

.

Thus, the answer is 37