# IMO Level 1- Mathematics Olympiad (SOF) Class 9: Questions 239 - 243 of 931

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## Question 239

### Question

MCQ▾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 240

### Question

MCQ▾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 241

### Question

MCQ▾From the adjoining figure . The value of x is ________

### Choices

Choice (4) | Response | |
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a. | ||

b. | ||

c. | ||

d. |

## Question 242

### Question

MCQ▾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 ________

### Choices

Choice (4) | Response | |
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a. | ||

b. | ||

c. | ||

d. |

## Question 243

### Question

MCQ▾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 |