**Question 1. The mean of first natural numbers**

Answer: C

**Explanation:****Question 2. The mean of first n natural numbers 4n/7.then n=......**

Answer: C

**Explanation:****Question 3. Mean of 100 items is 49.It was observed that three items which should have 60,70 and 80 were worngly read as 40,20 and 50 respectively.What is the value of correct mean?**

Answer: C

**Explanation:****Question 4. Mean of 100 items is 49.It was observed that three items which should have 60,70 and 80 were worngly read as 80,50 and 1800 respectively.What is the value of correct mean?**

Answer: C

**Explanation:****Question 5. The mean of N observations is M. If sum of N-4 observation is A then mean of remaining 4 observations is**

Answer: A

**Explanation:****Question 6.The average score of boys in the examination of a school is 71 and that of the the girls is 73. The average score of the school in the examination is 71.8. Find the ratio of the number of boys to the number of girls who appeared in the examination.**

Answer: A

**Explanation:****Question 7. If the 2nd term of an AP is 13 and the 5th term is 25, then its 7th term is**

Answer: A

**Explanation:****Question 8. The ——— of observations is the sum of the values of all the observations divided by the total number of observations.**

Answer: A

**Explanation:****Question 9. Half of (upper class limit + lower class limit) is —————-**

Answer: B

**Explanation:****Question 10. The arithmetic mean of a set of 10 numbers is 20. If each number is first multiplied by 2 and then increased by 5, then what is the mean of new numbers?**

Answer: D

**Explanation:**