Elyse spent ⁴₅ of her money on 13 notebooks and 9 staplers. The cost of each stapler is 3 times the cost of each notebook. She bought some more notebooks with ⁴₅ of her remaining money. How many notebooks did Elyse buy altogether?

13 notebooks + 9 staplers		Remaining  amount		Total amount
4 p = 40 u		1 p = 10 u		5 p
13 notebooks	9 staplers	More notebooks	Left
		4	1
13 u	27 u	8 u

Cost of 1 notebook = 1 u
Cost of 1 stapler = 3 u

Cost of 13 notebooks = 13 x 1 u = 13 u
Cost of 9 staplers = 9 x 3 u = 27 u

Cost of 13 notebooks + 9 staplers
= 13 u + 27 u
= 40 u

4 p = 40 u

1 p = 40 u ÷ 4 = 10 u

Amount of remaining money that Elyse spent on buying more notebooks
= ⁴₅ x 10 u
= 8 u

Number of notebooks that Elyse bought with ⁴₅ of her remaining money
= 8 u ÷ 1 u
= 8

Total number of notebooks that Elyse bought
= 13 + 8
= 21

Answer(s): 21