11 P5.ST.JC.18121204
Level 3
The average cost of some books is $30.
When a book that costs $90 is removed,
the average cost of the books becomes $10.
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
12 P5.ST.JC.18121205
Level 3
The average cost of some books is $30.
If 3 of the books are now each $15 more,
the average cost of the books becomes $35.
How many books are there altogether?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table
13 P5.ST.JC.18121206
Level 3
The average cost of some books is $30.
If 3 of the books are now each $15 more and
2 of the books are now each $5 less,
the average cost of the books becomes $32.
How many books are there altogether?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table
14 P5.ST.JC.18121207
Level 3
The average cost of some books is $10.
After 2 new books are added,
it adds another $60 to the total cost.
As a result, the average cost of all the books increases to $20.
How many books are there at first?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table
15 P5.ST.JC.18121208
Level 3
The average cost of some books is $30.
After 2 new books are added,
it adds another $10 to the total cost.
As a result, the average cost of all the books decreases to $20.
How many books are there at first?
3 m
2 averages Averaging out Average with unknown quantity Number x value Units equations Units table
16 P5.DA.NK.23012603
Level 1
The average mass of Perry, Ethan and Tom is 36 kg. The average mass of Perry and Ethan is 34 kg. Find Tom's mass.
2 m
2 averages Mass
17 P5.DA.NK.23052638
TRY FOR FREE
Level 1
The average cost of a duck and 6 turkeys is $10.20. The average cost of each turkey is $9.90. How much does the duck cost?
2 m
Attempt
2 averages Number x value Money
18 P5.DA.NK.23012619
Level 1
A family's average monthly spending for August and September was $713. Their average monthly spending from October to December was $824. What was their total spending from August to December?
2 m
2 Averages Money Duration
19 P5.DA.JM.17083143
Level 1
The average of two numbers is 124 and the average of another set of two numbers is 262. Find the average of these four numbers.
2 m
Averaging out 2 averages Number x value Units table
20 P5.DA.NK.23052622
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Level 2
A group of 50 girls and 20 boys took part in a Mathematics test. The average score of the girls was 50 points. While the average score of the boys was 64 points. What was the average score of all the students who participated in the test?
2 m
Attempt
Averaging out 2 averages Number x value Units table

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