If sum of two numbers be a and their product be b, then the sum of their reciprocals is :

The difference between three times and seven times of a number comes to 36. What is the number?

Of the three numbers, the sum of the first two is 55, sum of the second and third is 65, and sum of third with thrice of…

Which one of the following is a factor of the sum of first twenty-five natural numbers ?

$$\frac{{\left[ {\left( {888 \times 888 \times 888} \right) - \left( {222 \times 222 \times 222} \right)} \right]}}{{\le…

The sum of four consecutive two-digit odd numbers, when divided by 10, become a perfect square. Which of the following c…

$$0.\overline {142857} \div 0.\overline {285714} \,$$    is equal to :

The number of two digit prime numbers which remain prime even inverting the position of its digits is: