The average cost of 6 books is $90.
After 3 books are removed,
the average cost of the remaining books is $40.
- 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 6 books
= 6 x 90
= $540
Number of remaining books
= 6 - 3
= 3
Total cost of the remaining books
= 3 x 40
= $120
Total cost of the 3 books that are removed
= 540 - 120
= $420
(b)
Average cost of the 3 books that are removed
= 420 ÷ 3
= $140
Answer(s): (a) $420; (b) $140