The average cost of 3 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 3 textbooks
= 3 x 60
= $180
New total cost of all the textbooks
= 180 + 80
= $260
(b)
New total number of textbooks
= 3 + 1
= 4
New average cost of all the textbooks
= 260 ÷ 4
= $65
Answer(s): (a) $260; (b) $65