Daniel, Susan and Rick bought some cookies to sell. The cookies were sold at 6 for $2. Daniel sold 1/4 of the cookies. Susan sold 2/7 as many cookies as Rick. Daniel and Susan sold a total of 120 cookies.

Question

a)How many cookies did they sell altogether?
b)How much did they collect from the cookies sold?
c)If the cookies costs $0.20 each, how much profit did they make from the sale?

Answer 1

X = total # of cookies bought.

X/4 = The # of cookies sold by Daniel.

Y = The # of cookies sold by Rick.

2Y/7 = The # of cookies sold by Susan.

X/4 + 2Y/7 = 120 = The # of cookies sold by Daniel and Susan.
Multiply both sides by 28:

Eq1: 7x + 8y = 3360.

y = x - 120,
Eq2: x - y = 120.

Multiply Eq2 by 8 and add to Eq1:
7x + 8y = 3360
8x - 8y = 960
Sum: 15x = 4320,
X = 288 = The # of cookies sold.

Answer 2

b. Amt = $2/6 * 288 = $96.

c. Cost = $.20 * 288 = $57.60.

Profit = $96 - $57.60 = $38.40.