The average cost of 5 books is $80.
After 3 books are removed,
the average cost of the remaining books is $20.
- 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 5 books
= 5 x 80
= $400
Number of remaining books
= 5 - 3
= 2
Total cost of the remaining books
= 2 x 20
= $40
Total cost of the 3 books that are removed
= 400 - 40
= $360
(b)
Average cost of the 3 books that are removed
= 360 ÷ 3
= $120
Answer(s): (a) $360; (b) $120