The average cost of 7 books is $80.
After 3 books are removed,
the average cost of the remaining books is $50.
- 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 7 books
= 7 x 80
= $560
Number of remaining books
= 7 - 3
= 4
Total cost of the remaining books
= 4 x 50
= $200
Total cost of the 3 books that are removed
= 560 - 200
= $360
(b)
Average cost of the 3 books that are removed
= 360 ÷ 3
= $120
Answer(s): (a) $360; (b) $120