Esther bought some Social Science books at $10 each. She also bought an equal number of Chemistry books at a different price. The average price of one Social Science and one Chemistry book was $8. Esther paid $20 less for the Chemistry books than the Social Science books.
- What was the cost of one Chemistry book?
- How many Social Science books did Esther buy?
|
Social Science |
Chemistry |
Less |
Number |
1 u |
1 u |
|
Value |
$10 |
$6 |
|
Total value |
10 u |
6 u |
$20 |
(a)
Price of one Chemistry book
= 2 x 8 - 10
= 16 - 10
= $6
Amount that Esther paid less for Chemistry books than Social Science books
= 10 u - 6 u
= 4 u
4 u = 20
1 u = 20 ÷ 4 = 5
Number of Social Science books that Esther bought
= 1 u
= 5
Answer(s): (a) $6; (b) 5