In a stationery shop, 4 pencils and 5 files cost $19.60. Joseph bought 5 pencils and 6 files at $23.80 from the book shop.
- Find the cost of 1 pencil and 1 file.
- What was the cost of 1 file?
(a)
Let 1 pencil be 1 P.
Let 1 file be 1 F.
4 P + 5 F = 19.60 --- (1)
5 P + 6 F = 23.80 --- (2)
(2) - (1)
1 P + 1 F = 23.80 --- 19.60
1 P + 1 F = 4.20 --- (3)
Cost of 1 pencil and 1 file = $4.20
(b)
(3)
x4 4 P + 4 F = 16.80 --- (4)
(1) - (4)
1 F = 19.60 - 16.80 = $2.80
Cost of 1 file = $2.80
Answer(s): (a) $4.20; (b) $2.80