In a stationery shop, 3 markers and 4 notebooks cost $23.50. Joseph bought 4 markers and 5 notebooks at $30.10 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.
3 M + 4 N = 23.50 --- (1)
4 M + 5 N = 30.10 --- (2)
(2) - (1)
1 M + 1 N = 30.10 --- 23.50
1 M + 1 N = 6.60 --- (3)
Cost of 1 marker and 1 notebook = $6.60
(b)
(3)
x3 3 M + 3 N = 19.80 --- (4)
(1) - (4)
1 N = 23.50 - 19.80 = $3.70
Cost of 1 notebook = $3.70
Answer(s): (a) $6.60; (b) $3.70