Question

Cookies are on sale, they cost 75 cents less than normal, if you buy 7 they cost $2.80, what is the normal price of cookies?

Original price = 1.15
Sale price = 0.40

Should be answered as a simultaneous equation. Help me:/

Answer 1

Explanation:

Let $x be the normal price and $y be the sale price.

y = x-0.75 ---(1)

7y = 2.80 ---(2)

(1)x7 : 7y = 7(x-0.75) ---(3)

(2) - (3) : 2.80 - 7(x-0.75) = 0

2.80 = 7(x-0.75)

x-0.75 = 0.40 ---(4)

x = 1.15

Sub (4) into (1)

y = 0.40.

Therefore the normal price is $1.15 and the sale price is $0.40.