1 Needs to be added. Sum of first 3 Prime Nos = 2+3+5 = 10. 7 is the fourth Prime No and 11 is the fifth.
So 10+1 = 11. Hence 1 needs to be added.
I am a three digit number. The sum of the first and last digits is equal to 16. The sum of the first two digits is equal to 7. What am I?
Find three number such that?
Is it possible to write down 1,2,3..100 in some order (one after an other), such that the sum of any two adjacent numbers is a prime number?
Saurabh was asked to find the average of first 'n' natural numbers. By mistake, he added a number twice but he didn't noticed it. As a result, he obtained a wrong average of 31.3. Find the number he added twice?