The average cost of 4 textbooks is $60.
After another textbook that costs $80 is added,
- What is new total cost of all the textbooks?
- What is new average cost of all the textbooks?
(a)
Total cost of 4 textbooks
= 4 x 60
= $240
New total cost of all the textbooks
= 240 + 80
= $320
(b)
New total number of textbooks
= 4 + 1
= 5
New average cost of all the textbooks
= 320 ÷ 5
= $64
Answer(s): (a) $320; (b) $64