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?
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?
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 PSLE
The average height of a group of children was 139.4 cm.
When Mr Tan measured and recorded the height of these children, he wrongly recorded one child's height as 181 cm when it should have been 118 cm. As a result, Mr Tan calculated the average height as 142.4 cm. How many children were there in the group?
Level 2 PSLE
The table shows the number of books read by each child in a class of 21 children. One of the numbers in the table is covered by an ink blot. The average number of books read by the children in the class is 6. What is the number covered by the ink blot?
Level 2 PSLE
The table shows the number of books read by each child in a class of 21 children. One of the numbers in the table is covered by an ink blot. The average number of books read by the children in the class is 6. What is the number covered by the ink blot?
Level 3
Some pupils took a Math exam. Their average score was 74.7 marks. One of the pupils' scores was wrongly recorded as 68 marks instead of 86 marks. As a result, the average score was calculated as 73.5 marks. How many pupils sat for the exam?
Level 3
The average mass of a group of girls was 37 kg. When Jamie, a girl, joined the group, the average mass of the group became 34 kg. If Jamie had a mass of 22 kg, how many girls were there in the group in the end?
Level 3
The average height of some boys is 145 cm. When 3 girls, with a total height of 393 cm, are included, the average height if the children becomes 142 cm. How many children are there altogether?
Level 3
Simon has some black and red balls. The total mass of all his balls is 242 g. He has 5 more red balls than black balls. The average mass of the black balls is 6 g. The average mass of the red balls is 10 g. How many balls does Simon have altogether?
Level 3
Kylie bought some Geography books at $17 each. She also bought an equal number of History books at a different price. The average price of one Geography and one History book was $10. Kylie paid $70 more for the Geography books than the History books.
Level 3
The average mass of a group of girls is 45 kg. If one more girl who weighs 75 kg joins the group, the new average mass of the group will become 48 kg. Find the total number of girls in the group.
Level 3
The average number of pages Joan read in a certain number of days was 15. In the next four days, Joan read another 88 pages. As a result, the average number of pages she read increased to 17. How many days did Joan read in total?
Level 3
The average test score of a class was 60 marks. After two students who scored an average marks of 96 marks transferred out of the class, the average score of the remaining students became 58 marks. How many students were there in the class at first?
Level 3
The average amount of money collected by a group of students at a flag day event was $125. When another 15 students turned up to help, the total amount donated increased by $1275 and the average amount of money collected became $113. How many students were there in the group at first?
