Level 3
In a pouch of notes, the number of $2, $5 and $10 are in ratio of 5 : 4 : 6. 15 of the $2-notes and 15 $5-notes are taken out. The remaining notes are worth $541. Find the difference between the value of $10-notes and $2-notes in the end.
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 ratio of the number of $2-notes to $10-notes in Dana's bag was 1 : 3. Dana exchanged 14 pieces of $10-notes for $2-notes. She then had an equal number of $2-notes and $10-notes. What was the total value of $2-notes and $10-notes in Dana's bag at first?
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?
