Gem bought some Chemistry books at $13 each. She also bought an equal number of English books at a different price. The average price of one Chemistry and one English book was $10. Gem paid $66 more for the Chemistry books than the English books.
- What was the cost of one English book?
- How many Chemistry books did Gem buy?
|
Chemistry |
English |
More |
Number |
1 u |
1 u |
|
Value |
$13 |
$7 |
|
Total value |
13 u |
7 u |
$66 |
(a)
Price of one English book
= 2 x 10 - 13
= 20 - 13
= $7
Amount that Gem paid more for Chemistry books than English books
= 13 u - 7 u
= 6 u
6 u = 66
1 u = 66 ÷ 6 = 11
Number of Chemistry books that Gem bought
= 1 u
= 11
Answer(s): (a) $7; (b) 11