The average cost of 8 books is $90.
After 3 books are removed,
the average cost of the remaining books is $60.
- What is the total cost of the 3 books that are removed?
- What is the average cost of the 3 books that are removed?
(a)
Total cost of 8 books
= 8 x 90
= $720
Number of remaining books
= 8 - 3
= 5
Total cost of the remaining books
= 5 x 60
= $300
Total cost of the 3 books that are removed
= 720 - 300
= $420
(b)
Average cost of the 3 books that are removed
= 420 ÷ 3
= $140
Answer(s): (a) $420; (b) $140