Answer:
£1.31
Step-by-step explanation:
The cakes are sold in the ratio 5 : 7 : 12 = 5x : 7x : 12x ( x is a multiplier )
sum the parts of the ratio, 5x + 7x + 12x = 24x
Equate 24x to the number of cakes sold, that is
24x = 216 ( divide both sides by 24 )
x = 9
Thus cakes sold are
5x = 5 × 9 = 45 small cakes
7x = 7 × 9 = 63 medium cakes
12x = 12 × 9 = 108 large cakes
let p represent the profit on a small cake, then
45p + 63(2p) + 108(3p) = 648.45 , that is
45p + 126p + 324p = 648.45
495p = 648.45 ( divide both sides by 495 )
p = 1.31
That is the profit on one small cake is £1.31
