Percentages: แบบฝึกหัด

A school club has 24 boys and 36 girls. What is the ratio of the number of boys to the total number of students in the club, expressed in its simplest form?

The ratio of the number of apple trees to orange trees in an orchard is \( 7 : 4 \). If there are 84 apple trees, what is the total number of trees in the orchard?

The price of a laptop was \$5,500. During a sale, it is sold at a discount of \( 15\% \). If a customer uses a membership card, they get an additional \( 5\% \) discount on the discounted price. What is the final price of the laptop?

In a library, there are \( 500 \) books. \( 45\% \) of the books are fiction, and the rest are non-fiction. How many non-fiction books are there in the library?

A bag contains red and blue marbles. The ratio of the number of red marbles to the number of blue marbles is \(3 : 5\). If there are 40 blue marbles, how many red marbles are there?

A sports store sold 240 basketballs last month. This month, it sold 300 basketballs. Find the percentage increase in the number of basketballs sold.

There are \(160\) students in a school hall. If \(35\%\) of them are boys and the rest are girls, what is the ratio of the number of boys to the number of girls in its simplest form?

A fruit juice mixture is made by mixing orange juice and water. The mixture contains \(65\%\) orange juice. If a bottle contains \(455\text{ mL}\) of orange juice, how much water, in \(\text{mL}\), is in the bottle?