Rachel bought some Physics books at $7 each. She also bought an equal number of Biology books at a different price. The average price of one Physics and one Biology book was $5. Rachel paid $12 less for the Biology books than the Physics books.
- What was the cost of one Biology book?
- How many Physics books did Rachel buy?
|
Physics |
Biology |
Less |
Number |
1 u |
1 u |
|
Value |
$7 |
$3 |
|
Total value |
7 u |
3 u |
$12 |
(a)
Price of one Biology book
= 2 x 5 - 7
= 10 - 7
= $3
Amount that Rachel paid less for Biology books than Physics books
= 7 u - 3 u
= 4 u
4 u = 12
1 u = 12 ÷ 4 = 3
Number of Physics books that Rachel bought
= 1 u
= 3
Answer(s): (a) $3; (b) 3