Nora spent
23 of her money on 13 pens and 9 notebooks. The cost of each notebook is 3 times the cost of each pen. She bought some more pens with
12 of her remaining money. How many pens did Nora buy altogether?
| 13 pens + 9 notebooks |
Remaining
amount |
Total
amount |
| 2 p = 40 u |
1 p = 20 u |
3 p |
13
pens |
9
notebooks |
More pens |
Left |
|
| |
|
1 |
1 |
|
| 13 u |
27 u |
10 u |
|
|
Cost of 1 pen = 1 u
Cost of 1 notebook = 3 u
Cost of 13 pens = 13 x 1 u = 13 u
Cost of 9 notebooks = 9 x 3 u = 27 u
Cost of 13 pens + 9 notebooks
= 13 u + 27 u
= 40 u
2 p = 40 u
1 p = 40 u ÷ 2 = 20 u
Amount of remaining money that Nora spent on buying more pens
=
12 x 20 u
= 10 u
Number of pens that Nora bought with
12 of her remaining money
= 10 u ÷ 1 u
= 10
Total number of pens that Nora bought
= 13 + 10
= 23
Answer(s): 23
