In a shop, 4 markers and 5 files cost $16.10. Joseph bought 5 markers and 6 files at $19.80 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.
4 M + 5 F = 16.10 --- (1)
5 M + 6 F = 19.80 --- (2)
(2) - (1)
1 M + 1 F = 19.80 --- 16.10
1 M + 1 F = 3.70 --- (3)
Cost of 1 marker and 1 file = $3.70
(b)
(3)
x4 4 M + 4 F = 14.80 --- (4)
(1) - (4)
1 F = 16.10 - 14.80 = $1.30
Cost of 1 file = $1.30
Answer(s): (a) $3.70; (b) $1.30