In a stationery shop, 4 markers and 5 notebooks cost $17.90. Joseph bought 5 markers and 6 notebooks at $21.70 from the book shop.
- Find the cost of 1 marker and 1 notebook.
- What was the cost of 1 notebook?
(a)
Let 1 marker be 1 M.
Let 1 notebook be 1 N.
4 M + 5 N = 17.90 --- (1)
5 M + 6 N = 21.70 --- (2)
(2) - (1)
1 M + 1 N = 21.70 --- 17.90
1 M + 1 N = 3.80 --- (3)
Cost of 1 marker and 1 notebook = $3.80
(b)
(3)
x4 4 M + 4 N = 15.20 --- (4)
(1) - (4)
1 N = 17.90 - 15.20 = $2.70
Cost of 1 notebook = $2.70
Answer(s): (a) $3.80; (b) $2.70