# IGCSE Mathematics Paper-1: Specimen Questions with Answers 70 - 72 of 175

## Question number: 70

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### Write in Short

(a) Find the value of y when.

(b) Make r the subject of the formula.

### Explanation

Here, equation is where,

(a)

(b)

## Question number: 71

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### Write in Short

(a) The surface area of the earth is . Write this number to 3 significant digits.

(b) 72.2 % of the surface area of the earth is water. Calculate the area of water.

### Explanation

Here,

(a) The surface area of the earth is

• So, correct it to 3 significant digits we will get: because after 0 there is 1 which is less than 5, so 0 will remain same.

(b) 72.2 % of the surface area of the earth is water.

So, here surface area 100 %= 510 million

Then 72.2 %=?

So, surface area of water on earth which is sphere = .

So, for area of water on earth is:

## Question number: 72

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Essay Question▾

### Describe in Detail

In a Hospital there are many types of the members and No. of members, which are shown in the table below.

 Types of members No. of Members Doctors 25 Nurses 50 Peons 35 Patients 78

Draw a bar chart below to show this data. Show your scale on the vertical axis and label the bars.