The average cost of 3 non-fiction books is $30.
After a non-fiction book that costs $80 is removed,
- What is new total cost of all the remaining non-fiction books?
- What is new average cost of all the remaining non-fiction books?
(a)
Total cost of 3 non-fiction books
= 3 x 30
= $90
New total cost of all the remaining non-fiction books
= 90 - 80
= $10
(b)
Number of remaining non-fiction books
= 3 - 1
= 2
New average cost of all the remaining non-fiction books
= 10 ÷ 2
= $5
Answer(s): (a) $10; (b) $5