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

## Question number: 70

### 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

### 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

### 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.

### Explanation

**{point.y}**"},"credits":{"enabled":false},"xAxis":{"categories":["Doctors"," Nurses"," Peons"," Patients"],"title":{"text":"Types of members"}},"yAxis":{"type":"linear","title":{"text":"No. of members"}},"plotOptions":{"series":{"allowPointSelect":true,"cursor":"pointer"}},"legend":{"floating":true,"backgroundColor":"white","borderColor":"silver","borderWidth":1,"shadow":true},"series":[{"type":"column","name":"Number of members versus type of members","data":[25,50,35,78],"colors":[{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#7cb5ec"],[1,"rgb(48,105,160)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#434348"],[1,"rgb(0,0,0)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#90ed7d"],[1,"rgb(68,161,49)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#f7a35c"],[1,"rgb(171,87,16)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#8085e9"],[1,"rgb(52,57,157)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#f15c80"],[1,"rgb(165,16,52)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#e4d354"],[1,"rgb(152,135,8)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#2b908f"],[1,"rgb(0,68,67)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#f45b5b"],[1,"rgb(168,15,15)"]]},{"linearGradient":{"x1":0,"y1":0,"x2":0,"y2":1},"stops":[[0,"#91e8e1"],[1,"rgb(69,156,149)"]]}]}]}