# IMO Level 1- Mathematics Olympiad (SOF) Class 9: Questions 239 - 243 of 929

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## Question number: 239

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MCQ▾

### Question

27 metal balls each of radius r are melted together to from one big sphere of radius R. Then the ratio of surface area of the big sphere to that of a ball is ________

### Choices

Choice (4) Response

a.

3

b.

c.

d.

9

## Question number: 240

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MCQ▾

### Question

A running track is the ring formed by two concentric circles. It is 15 feet wide. The circumferences of the two circles differ by about ________

### Choices

Choice (4) Response

a.

65 feet

b.

94 feet

c.

75 feet

d.

90 feet

## Question number: 241

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MCQ▾

### Question

From the adjoining figure . The value of x is ________

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 242

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MCQ▾

### Question

A rectangle is divided into four smaller rectangles, as shown in the figure. Three of them have areas, and as indicated. Then the area of the shaded rectangle is ________ Given the Rectangle is Divided into Four Rectangles Given the rectangle is divided into four smaller rectangles and three of them have area 9 units, 21 units, 38 unit as indicated and find the area of the shaded rectangle

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 243

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MCQ▾

### Question

C1 is a circle of radius 4 cm, C2 is a circle of radius 12 cm. Jyoti wants the two circles to touch tangentially. She knows that there are two possibilities for the distance between their centers. What are these two distances?

### Choices

Choice (4) Response

a.

8 cm and 16 cm

b.

10 cm and 16 cm

c.

8 cm and 10 cm

d.

13 cm and 4 cm