The average cost of 7 books is $80.
After 4 books are removed,
the average cost of the remaining books is $60.
- 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 80
= $560
Number of remaining books
= 7 - 4
= 3
Total cost of the remaining books
= 3 x 60
= $180
Total cost of the 4 books that are removed
= 560 - 180
= $380
(b)
Average cost of the 4 books that are removed
= 380 ÷ 4
= $95
Answer(s): (a) $380; (b) $95