In a stationery kiosk, 4 files and 5 pencils cost $25.70. Joseph bought 5 files and 6 pencils at $31.50 from the book shop.
- Find the cost of 1 file and 1 pencil.
- What was the cost of 1 pencil?
(a)
Let 1 file be 1 F.
Let 1 pencil be 1 P.
4 F + 5 P = 25.70 --- (1)
5 F + 6 P = 31.50 --- (2)
(2) - (1)
1 F + 1 P = 31.50 --- 25.70
1 F + 1 P = 5.80 --- (3)
Cost of 1 file and 1 pencil = $5.80
(b)
(3)
x4 4 F + 4 P = 23.20 --- (4)
(1) - (4)
1 P = 25.70 - 23.20 = $2.50
Cost of 1 pencil = $2.50
Answer(s): (a) $5.80; (b) $2.50