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
Liam and Tim share a bunch of chikoos in the ratio 5 : 3. If Liam gives Tim 23 chikoos from his share, they will have the same number of chikoos. How many chikoos does Liam have at first?
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?