The average cost of 6 books is $60.
After 3 books are removed,
the average cost of the remaining books is $30.
- 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 60
= $360
Number of remaining books
= 6 - 3
= 3
Total cost of the remaining books
= 3 x 30
= $90
Total cost of the 3 books that are removed
= 360 - 90
= $270
(b)
Average cost of the 3 books that are removed
= 270 ÷ 3
= $90
Answer(s): (a) $270; (b) $90