The average cost of 7 books is $60.
After 4 books are removed,
the average cost of the remaining books is $40.
- 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 60
= $420
Number of remaining books
= 7 - 4
= 3
Total cost of the remaining books
= 3 x 40
= $120
Total cost of the 4 books that are removed
= 420 - 120
= $300
(b)
Average cost of the 4 books that are removed
= 300 ÷ 4
= $75
Answer(s): (a) $300; (b) $75