# IMO Level 1- Mathematics Olympiad (SOF) Class 10: Questions 639 - 646 of 968

Access detailed explanations (illustrated with images and videos) to 968 questions. Access all new questions- tracking exam pattern and syllabus. View the complete topic-wise distribution of questions. Unlimited Access, Unlimited Time, on Unlimited Devices!

View Sample Explanation or View Features.

Rs. 450.00 -OR-

How to register? Already Subscribed?

## Question 639

### Question

MCQ▾

If ‘a’ is the A. M. of 3 numbers and ‘b’ is the A. M. of their squares, then the A. M. of their pair-wise products in terms of a and b is ________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 640

### Question

MCQ▾

The value of is ________

### Choices

Choice (4)Response

a.

420

b.

210

c.

195

d.

390

## Question 641

### Question

MCQ▾

If four numbers are in A. P. such that their sum is 90 and the greatest number is 4 times the least, then the numbers are ________

### Choices

Choice (4)Response

a.

b.

c.

d.

Question does not provide sufficient data or is vague

## Question 642

### Question

MCQ▾

Between the numbers 7 and 70,28 means are inserted, then their sum is ________

### Choices

Choice (4)Response

a.

1795

b.

1078

c.

1695

d.

1895

## Question 643

### Question

MCQ▾

In an A. P, If it is given that then is equal to ________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 644

### Question

MCQ▾

The value of is ________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 645

### Question

MCQ▾

If up to n terms and n is even, then S equals________

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question 646

### Question

MCQ▾

Let denotes the sum of n terms of an A. P. , whose first term is a. if the common difference d is given by then K is equal to ________ ________

### Choices

Choice (4)Response

a.

4

b.

1

c.

3

d.

2