Using percentages：練習問題

A collection of stamps consists of 450 stamps. If the number of stamps in the collection increases by 12%, what is the new total number of stamps?

A sum of \$20,000 is deposited in a bank at an interest rate of 8% per annum, compounded annually. What is the total interest earned after 2 years?

The side length of a square floor tile is increased by \( 30% \). What is the percentage increase in the area of the tile?

A factory produced \( 2500 \) units of a product last month. This month, the production increased to \( 3100 \) units. Find the percentage increase in production.

A property's value increased by 15% last year. This year, its value decreased by 10%. What is the overall percentage change in the property's value over these two years?

A student scored \( 48 \) marks out of \( 60 \) in a mathematics test. Express this score as a percentage.

A sum of \$8,000 is deposited into a bank at a simple interest rate of 4.5% per annum for 2 years. Find the total amount (principal + interest) at the end of the period.

A sum of \$15,000 is deposited in a bank at a simple interest rate of 3% per annum. Find the total interest earned after 18 months.

A town's population increased by \(10\%\) last year. If the current population is \(13\,200\) people, what was the population before the increase?

A fashion boutique is reviewing its pricing and sales performance for a designer handbag.
(a) The cost price of the handbag is \$1,200. The shop owner marks up the price by 40%. What is the marked price of the handbag?
(b) During a seasonal promotion, the shop offers a 15% discount on the marked price. Calculate the selling price during the sale.
(c) At the end of the year, the value of the handbag (selling price from part b) is expected to depreciate by 10%. What will be the estimated value of the handbag after this depreciation?