Question

3. If pencils cost 15 cents each, and notebooks cost 85 cents each, find the number of pencils

purchased if 50 items cost $18.00.

Answer 1

if a pencils is 15 cents each and a notebook is 85 so .85+.15= one

Answer 2

Pencils = 35

Notebooks = 15

Explanation:

15 cents = 15/100 = $0.15

85 cents = 85/100 = $0.85

p + n = 50 Eq. 1

0.15p + 0.85n = 18 Eq. 2

p = number of pencils

n = number of notebooks

From Eq. 1

p = 50 - n Eq. 3

Replacing Eq. 3 in Eq. 2:

0.15(50-n) + 0.85n = 18

(0.15*50 + 0.15*-n) + 0.85n = 18

(7.5 - 0.15n) + 0.85n = 18

7.5 + 0.7n = 18

0.7n = 18 - 7.5

0.7n = 10.5

n = 10.5 / 0.7

n = 15

From Eq. 3:

p = 50 - n

p = 50 - 15

p = 35

Check:

From Eq. 2

0.15p + 0.85n = 18

0.15*35 + 0.85*15 = 18

5.25 + 12.75 = 18

e