Question

(!!WORD PROBLEM!!)

You go grocery shopping and spend a total of $40. You purchase 4 boxes of cookies and 4 bags of chips. Your
friend also goes grocery shopping and purchases 3 boxes of cookies and 5 bags of chips for a total of $40.
How much did each package of cookies and each bag of chips cost?​

Answer 1

Answer: a package of cookies cost $ 5 and each bag of chips cost $5

Explanation:

Let x represent the cost of a package of cookies and y represent the cost of a bap of chips ,then from the first statement :

4x + 4y = 40

dividing through by 4 , we have

x + y = 10 ........................... equation 1

From the second statement

3x + 5y = 40 ..................... equation 2

Solving the system of linear equation by substitution method , from equation 1 , make x the subject of the formula , that is

x = 10 - y ................... equation 3

substitute x = 10 - y into equation 2 , we have :

3 (10 - y ) + 5y = 40

30 - 3y + 5y = 40

30 + 2y = 40

subtract 30 from both sides

2y = 40 -30

2y = 10

y = 5

substitute y = 5 into equation 3 , equation 3 becomes

x = 10 - 5

x = 5

Therefore ; a package of cookies cost $ 5 and each bag of chips cost $5