The average cost of 5 textbooks is $30.
After another textbook that costs $90 is added,
- What is new total cost of all the textbooks?
- What is new average cost of all the textbooks?
(a)
Total cost of 5 textbooks
= 5 x 30
= $150
New total cost of all the textbooks
= 150 + 90
= $240
(b)
New total number of textbooks
= 5 + 1
= 6
New average cost of all the textbooks
= 240 ÷ 6
= $40
Answer(s): (a) $240; (b) $40