6 P5.ST.JC.18121194
Level 2
The average cost of 5 books is $30.
After 2 books are removed,
the average cost of the remaining books is $20.
  1. What is the total cost of the 2 books that are removed?
  2. What is the average cost of the 2 books that are removed?
3 m
2 averages Averaging out
7 P5.ST.JC.18121195
Level 2
The average cost of 5 books is $50.
After 2 new books are added,
the average cost of all the books is $40.
  1. What is the total cost of the 2 books that are added?
  2. What is the average cost of the 2 books that are added?
3 m
2 averages Averaging out
8 P5.ST.JC.18121200
Level 2
The average cost of 4 books is $30.
The average cost of 3 books is $10.
What is the cost of 4th book?
2 m
2 averages Average with unknown quantity
9 P5.ST.JC.18121202
Level 3
The average cost of some books is $75.
When another 3 books are added,
the total cost increases by $190.
The average cost becomes $70.
How many books are there in the end?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table
10 P5.ST.JC.18121203
Level 3
The average cost of some books is $30.
When a book that costs $90 is added,
the average cost of the books becomes $40.
How many books are there in the end?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table

5 per page

10 per page

20 per page

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