In a store, 3 staplers and 4 files cost $15.50. Joseph bought 4 staplers and 5 files at $19.80 from the book shop.
- Find the cost of 1 stapler and 1 file.
- What was the cost of 1 file?
(a)
Let 1 stapler be 1 S.
Let 1 file be 1 F.
3 S + 4 F = 15.50 --- (1)
4 S + 5 F = 19.80 --- (2)
(2) - (1)
1 S + 1 F = 19.80 --- 15.50
1 S + 1 F = 4.30 --- (3)
Cost of 1 stapler and 1 file = $4.30
(b)
(3)
x3 3 S + 3 F = 12.90 --- (4)
(1) - (4)
1 F = 15.50 - 12.90 = $2.60
Cost of 1 file = $2.60
Answer(s): (a) $4.30; (b) $2.60