Question

Sam wants to buy 8 pencils and 6 pens, Wich cost a total of $8.50. He realizes he doesn’t have enough cash and instead takes only 4 of each, which cost only $5. What is the price of each pen and pencil

Answer 1

n = 0.75

p = 0.5

Explanation:

let p = number of pencils

let n = number of pens

8p + 6n = 8.50 (1)

4p + 4n = 5 (2)

(2) x 2 8p + 8n = 10 (3)

8p + 6n = 8.50 (1)

8p + 8n = 10 (3)

(3) - (1) 2n = 1.50

n = 0.75

substitute n back in to find p

4p + 4 x 0.75 = 5

4p + 3 = 5

4p = 2

p = 0.5