Risa bought some Social Science books at $13 each. She also bought an equal number of English books at a different price. The average price of one Social Science and one English book was $11. Risa paid $8 more for the Social Science books than the English books.
- What was the cost of one English book?
- How many Social Science books did Risa buy?
|
Social Science |
English |
More |
Number |
1 u |
1 u |
|
Value |
$13 |
$9 |
|
Total value |
13 u |
9 u |
$8 |
(a)
Price of one English book
= 2 x 11 - 13
= 22 - 13
= $9
Amount that Risa paid more for Social Science books than English books
= 13 u - 9 u
= 4 u
4 u = 8
1 u = 8 ÷ 4 = 2
Number of Social Science books that Risa bought
= 1 u
= 2
Answer(s): (a) $9; (b) 2