The average cost of 8 books is $90.
After 4 books are removed,
the average cost of the remaining books is $70.
- 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 8 books
= 8 x 90
= $720
Number of remaining books
= 8 - 4
= 4
Total cost of the remaining books
= 4 x 70
= $280
Total cost of the 4 books that are removed
= 720 - 280
= $440
(b)
Average cost of the 4 books that are removed
= 440 ÷ 4
= $110
Answer(s): (a) $440; (b) $110