Product of digits of a 2-digit number is 27. If we add  54 to the number, the new number obtained is a number formed by interchange of the digits. Find the number.

The difference of a number consisting of two digits from the number formed by inter changing the digits is always divisible by: 

Sum of two numbers is thrice their difference. Their ratio is 

Find the average of all prime numbers from 1 to 20?

Find the value of $$ {1\over{2×5}}+{1\over {5×8}}+{1\over {8 × 11}}+......{1\over {23 × 26}}=?$$

What least value which should be added to 1812 to make it divisible 7,11 and 14? 

If the arithmetic means of 3a and 4b is greater than 50, and a is twice b, then the smallest possible integer value of a is: 

If an 8-digit number 1862383A is divisible by 22, find the value of A.