16) let h = the number of hours Marcus played. then Donnell played h+3. together they practiced for h+h+3=11 hours
h+h+3=11
2h+3=11
2h=8
h=4
Marcus practiced 4 and Donnell practiced 7 hours.
let c=price of each cupcake. then 24c+16=52
24c+16=52
24c=36
c=1.50 each for the cupcakes