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?
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?
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?
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?
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?
Level 2
Samantha scored a total of 98 marks for her History and Geography tests and a total of 130 marks for her Chinese and English tests. What was her average marks for the 4 subjects?
Level 2
There are 8 boys and 12 girls in a class. If each boy gets 15 sweets and each girl gets 20 sweets, what is the average number of sweets each child gets?
Level 3
William had some coins. 40% of his coins were made up of 50-cent coins which was equal to the number of $1 coins. The rest of the coins were made up of 20-cent coins. Given that William had $16 more 50-cent coins than 20-cent coins, how many coins did William have altogether?
