# IGCSE Mathematics Paper-1: Specimen Questions with Answers 19 - 22 of 175

## Question number: 19

### Write in Short

Solve the equations

(a) ,

(b)

### Explanation

Here,

(a)

(b)

## Question number: 20

### Describe in Detail

The population of a city is . It is expected that this population will increase by 42 % by the year 2008. Calculate the expected population in 2008.

### Explanation

Here, Population is.

Expected population will increase by 42%.

So, increment in population will: .

So, expected population will be

## Question number: 21

### Write in Short

Jerry changed $20 into euros with exchange rate was €1= $1.2685. How many euros did she receive? Answer in 2 decimal places.

### Explanation

Here, €1= $1.2685.

- Jerry changed $20 into euros.
- Where, exchange rate was

So,

- So, she received

## Question number: 22

### Describe in Detail

The diagram shows a cylindrical boiler. The radius is 40 cm and the height is 90 cm.

(a) Calculate the area of the base of the boiler.

(b) Calculate the volume of the boiler in liters.

### Explanation

Here, radius is 40 cm and height is 90 cm.

(a) **Area of base** of the boiler is a circle, so by using the formula of area of a circle:

(b) **Volume of the cylindrical boiler**:

Now,

So,

So,