The average cost of 9 textbooks is $30.
After a textbook that costs $70 is removed,
- What is new total cost of all the remaining textbooks?
- What is new average cost of all the remaining textbooks?
(a)
Total cost of 9 textbooks
= 9 x 30
= $270
New total cost of all the remaining textbooks
= 270 - 70
= $200
(b)
Number of remaining textbooks
= 9 - 1
= 8
New average cost of all the remaining textbooks
= 200 ÷ 8
= $25
Answer(s): (a) $200; (b) $25