# IMO Level 1- Mathematics Olympiad (SOF) Class 10: Questions 404 - 409 of 968

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## Question 404

### Question

MCQ▾

Two dice are thrown at a time. The probability that the difference of the numbers shown on the dice is 2 is ________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 405

### Question

MCQ▾

The mean of 20 observations is . if each observation is multiplied by 2, then what is the new mean?

### Choices

Choice (4)Response

a.

30

b.

60

c.

70

d.

50

## Question 406

### Question

MCQ▾

A box contains 40 balls of two different colours, out of which x are black. One ball is drawn at random. If 20 more black balls are put in the box, the probability of drawing a black ball now will be double that of the previous probability of drawing a black ball. Then, the value of x is ________

### Choices

Choice (4)Response

a.

12

b.

10

c.

15

d.

14

## Question 407

### Question

MCQ▾

A Motor maintains an average speed of 70 km/hr while going from P to Q and maintains an average speed of 85 km/hr while coming back from Q to P. the average speed of the motor is ________.

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 408

### Question

MCQ▾

is three vertices of the parallelogram PQRS. The coordinates of fourth vertex is ________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 409

### Question

MCQ▾

Four vertices of a parallelogram taken in order are . What will be the ratio of a and b?

### Choices

Choice (4)Response

a.

b.

1: 9

c.

2: 9

d.

3: 7