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
Tank E contained 4 times as many guppies as Tank F. When 10% of the guppies in Tank E and 10% of the guppies in Tank F were transferred to Tank G, Tank G had 120 guppies, which was 20% more guppies than before. How many less guppies were there in Tank F than Tank E in the end?
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
Vincent had some pastries. 27 of them were tarts. The rest were cookies. He sold 35 of the tarts and 14 cookies. In the end, he had 131 pastries left. How many more tarts than cookies did he sell?
