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Five pencils and three erasers cost $.65. Three pencils and two erasers cost $.40. Find the cost of one pencil and the cost of one eraser.

Respuesta :

let x = cost of one pencil
let y = cost of one eraser

5x+3y=65
3x+2y=40

10x+6y=130

9x+6y=120
subtract
x=10

2y=40-3x
2y=40-30=10
y=5

cost of one pencil=10 cents
cost of one eraser=5 cents

Hope this helps :)
choixongdong
5p + 3e = 0.65 (1st)
3p + 2e = 0.4 (2nd)

multiply (1st) equation by 2 and (2nd) equation by 3

10p + 6e = 1.3 (1st)
9p + 6e = 1.2 (2nd)
---------------------------------subtract
p = 0.1

10p + 6e = 1.3
10(0.1) + 6e = 1.3
1 + 6e = 1.3
6e = .3
e = 0.05

answer
one pencil = $.30 or 30 cents
eraser = $0.05 or 5 cents

hope it helps

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