Rachel bought some Chemistry books at $10 each. She also bought an equal number of Biology books at a different price. The average price of one Chemistry and one Biology book was $7. Rachel paid $24 more for the Chemistry books than the Biology books.
- What was the cost of one Biology book?
- How many Chemistry books did Rachel buy?
|
Chemistry |
Biology |
More |
Number |
1 u |
1 u |
|
Value |
$10 |
$4 |
|
Total value |
10 u |
4 u |
$24 |
(a)
Price of one Biology book
= 2 x 7 - 10
= 14 - 10
= $4
Amount that Rachel paid more for Chemistry books than Biology books
= 10 u - 4 u
= 6 u
6 u = 24
1 u = 24 ÷ 6 = 4
Number of Chemistry books that Rachel bought
= 1 u
= 4
Answer(s): (a) $4; (b) 4