Anna spent
45 of her money on 11 pens and 7 notebooks. The cost of each notebook is 3 times the cost of each pen. She bought some more pens with
78 of her remaining money. How many pens did Anna buy altogether?
| 11 pens + 7 notebooks |
Remaining
amount |
Total
amount |
| 4 p = 32 u |
1 p = 8 u |
5 p |
11
pens |
7
notebooks |
More pens |
Left |
|
| |
|
7 |
1 |
|
| 11 u |
21 u |
7 u |
|
|
Cost of 1 pen = 1 u
Cost of 1 notebook = 3 u
Cost of 11 pens = 11 x 1 u = 11 u
Cost of 7 notebooks = 7 x 3 u = 21 u
Cost of 11 pens + 7 notebooks
= 11 u + 21 u
= 32 u
4 p = 32 u
1 p = 32 u ÷ 4 = 8 u
Amount of remaining money that Anna spent on buying more pens
=
78 x 8 u
= 7 u
Number of pens that Anna bought with
78 of her remaining money
= 7 u ÷ 1 u
= 7
Total number of pens that Anna bought
= 11 + 7
= 18
Answer(s): 18
