Answer: 21 cupcakes and 33 cookies were sold.
Explanation:
Let x= Number of cupcakes
y = Number of cookies
As per given,
x+y= 54 (i)
Cost: 2.25x+0.25y=55.50 (ii)
Multiply 0.25 to (i0, we get
0.25x+0.25y = 0.25(54)
⇒0.25x+0.25y = 13.5 (iii)
subtract (iii) from (ii), we get
2x=42
Divide both sides by 2, we get x= 21
Put this in (i) , we get 21+y =54 ⇒ y= 54-21= 33
Hence, 21 cupcakes and 33 cookies were sold.