Level 3
The average mass of a group of 12 children is 33 kg and the average mass of another group of 18 children is 36 kg. What is the average mass of the two groups of children?
3 m
Level 3
Bryan went on a tour with his wife and two children. An average of $799 was spent on each child while an average of $1081 was spent on each adult. On the whole, what was the average amount spent on each person for the trip?
3 m
Level 3
A list of 13 numbers has an average of 330. When two numbers are deleted from the list, the average of the remaining numbers is 313.
  1. What is the sum of 13 numbers?
  2. What is the bigger number between the two numbers that have been deleted given that the difference between the two numbers is 1?
3 m
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Level 3
The average height of a group of 6 girls is 137 cm. When Kathy and Nicole joined the group, the average height increased by 4 cm. What is Kathy and Nicole's total height?
3 m
Level 3
Five numbers were written on the whiteboard as shown:
  1. Write down the 3 numbers that will give an average of 51.
  2. After John wrote 2 -digit number on the same whiteboard, the new average of the six numbers became a multiple of 3. What was the largest possible 2-digit number written by John?
3 m