Tammy spent
23 of her money on 10 pens and 7 notebooks. The cost of each notebook is 2 times the cost of each pen. She bought some more pens with
23 of her remaining money. How many pens did Tammy buy altogether?
| 10 pens + 7 notebooks |
Remaining
amount |
Total
amount |
| 2 p = 24 u |
1 p = 12 u |
3 p |
10
pens |
7
notebooks |
More pens |
Left |
|
| |
|
2 |
1 |
|
| 10 u |
14 u |
8 u |
|
|
Cost of 1 pen = 1 u
Cost of 1 notebook = 2 u
Cost of 10 pens = 10 x 1 u = 10 u
Cost of 7 notebooks = 7 x 2 u = 14 u
Cost of 10 pens + 7 notebooks
= 10 u + 14 u
= 24 u
2 p = 24 u
1 p = 24 u ÷ 2 = 12 u
Amount of remaining money that Tammy spent on buying more pens
=
23 x 12 u
= 8 u
Number of pens that Tammy bought with
23 of her remaining money
= 8 u ÷ 1 u
= 8
Total number of pens that Tammy bought
= 10 + 8
= 18
Answer(s): 18
