Diana bought 6 notebooks and 9 speakers. Each notebook costs $497 more than each speaker. She spent 25% of her money on the speakers.
- How much did each notebook cost?
- How much did she spend altogether?
| |
Notebooks |
Speakers |
Total |
| Number |
6 |
9 |
|
| Value |
1 u + $497 |
1 u |
|
| Total value |
6 u + $2982 |
9 u |
|
Comparing amounts
spent on notebooks
and speakers |
75%
|
25% |
100% |
(a)
Amount that Diana spent on the notebooks
= 6(1 u + 497)
= 6 u + 2982
Amount that Diana spent on the speakers
= 9 x 1 u
= 9 u
Amount that Diana spent on the notebooks in percent
= 100% - 25%
= 75%
25% → 9 u
75% → 3 x 9 u = 27 u
27 u = 6 u + 2982
27 u - 6 u = 2982
21 u = 2982
1 u = 2982 ÷ 21 = 142
Cost of each notebook
= 142 + 497
= $639
(b)
100% → 9 u + 27 u = 36 u
Amount that Diana spent altogether
= 36 u
= 36 x 142
= $5112
Answer(s): (a) $639; (b) $5112
