The average cost of 7 books is $40.
After 4 books are removed,
the average cost of the remaining books is $20.
- What is the total cost of the 4 books that are removed?
- What is the average cost of the 4 books that are removed?
(a)
Total cost of 7 books
= 7 x 40
= $280
Number of remaining books
= 7 - 4
= 3
Total cost of the remaining books
= 3 x 20
= $60
Total cost of the 4 books that are removed
= 280 - 60
= $220
(b)
Average cost of the 4 books that are removed
= 220 ÷ 4
= $55
Answer(s): (a) $220; (b) $55