In a stationery shop, 3 markers and 4 files cost $15.50. Joseph bought 4 markers and 5 files at $20.20 from the book shop.
- Find the cost of 1 marker and 1 file.
- What was the cost of 1 file?
(a)
Let 1 marker be 1 M.
Let 1 file be 1 F.
3 M + 4 F = 15.50 --- (1)
4 M + 5 F = 20.20 --- (2)
(2) - (1)
1 M + 1 F = 20.20 --- 15.50
1 M + 1 F = 4.70 --- (3)
Cost of 1 marker and 1 file = $4.70
(b)
(3)
x3 3 M + 3 F = 14.10 --- (4)
(1) - (4)
1 F = 15.50 - 14.10 = $1.40
Cost of 1 file = $1.40
Answer(s): (a) $4.70; (b) $1.40