Maths worksheets for challenging problem sums

Related Skills
Skill Involving Changing quantities

* Practice for skill involving changing quantities

1) Varsha had some 20-cent and 50-cent coins.
78 of the coins were 20-cent coins and the rest were 50-cent coins.
After Varsha had spent $72.50 worth of 50-cent coins and 57 of the 20-cent coins, she had 27 of the coins left. Find the total amount of money Varsha left.

Ans :- $110.20.

2) There are 36 pupils in a class. The ratio of the number of boys to the number of girls is 5 : 4. If 2 more boys join the class, what fraction of the class are girls? Express your answer in its simplest form.

Ans :- 819.

3) In a game, Parisse scored 240 more points than Max at first. After Parisse lost 332 points to her friend, Fendi, Max had 3 times as many points as Parisse. How many points did Parisse have at first?

Ans :- $378.

4) On Saturday, there were 50 more females than males at a concert. On Sunday, the number of females increased by 10% and the number of males decreased by 20%, resulting in 625 people at the concert. Each ticket cost $25. How much money was collected on Saturday?

Ans :- $16250.

5) In a box, the number of gold coins was 20% of the number of silver coins. Faizal added 8 more gold coins and 8 more silver coins into the box. As a result, there were ¼ as many gold coins as silver coins in the box. Find the total number of coins Faizal has in the end.

Ans :- 160 coins.

6) Kumar had 50% more bookmarks than Leon. Max had 75% as many bookmarks as Kumar. Kumar and Leon gave Max a number of bookmarks in the ratio 3 : 1. As a result, Max had twice as many bookmarks as before and Leon had 16 bookmarks more than Kumar. How many bookmarks did Kumar give to Max?

Ans :- 216.

7) Keith had some toy cars. He lost 0.3 of his toy cars and his mother bought him another 9 toy cars. The next day, he gave 0.25 of his toy cars to his best friend and had 75 toy cars left. How many toy cars did Keith have at first?

Ans :- Keith had 130 toy cars.

8) Daphne had 20% fewer books than Jocelyn. Yan Ming had 8 more books than Jocelyn. If Jocelyn were to give 4 books to Daphne, they would both have an equal number of books.
(a) How many books did the 3 girls have altogether?
(b) Yan Ming went to buy some new books. The ratio of books than Yan Ming had to the ratio that Jocelyn had then became 3 : 2. How many new books did Yan Ming buy?

Ans :- a) 120
b) 12.

9) The ratio of the number of ducks to the number of geese on Farmer Zhou's farm was 5 : 6. When Farmer Zhou acquired 242 more geese, there was an overall increase of 40% of the total number of ducks and geese he had at first.
(a) How many ducks and geese were there on Farmer Zhou's farm at the end?
(b) What was the percentage increase in the number of ducks on Farmer Zhou's farm?

Ans :- a) 847
b) 88% .

10 The ratio of Jamal's mass to Kathy's mass is 4 : 5. Jamal's mass is increased by 40% and Kathy's mass is decreased. What percentage of Kathy's mass must be decreased so that their total mass remains the same?

Ans :- 32% of her mass must be decreased.