The zeros of the cubic polynomial are a, b and c respectively. Find ab + bc + ca =?

What will be remainder if (13)³ is subtracted from (66)² ?

The sum of three consecutive numbers is 87. The middle number is : 

When a positive integer n is divided by 5 the remainder is 2. What is the remainder when the number 3n is is divided by 5 ?

What is the sum of two consecutive even numbers, the difference of whose square is 84? 

The numerator of a fraction is 4 less than its denominator. If the numerator is decreased by 2 and the denominator is increased by 1, the denominator becomes eight times the numerator. Find the fraction? 

The mean of the first 7 prime numbers is:

Find the least number which when divided by 12, 15, 18 and 27 leaves remainders 10, 13, 16 and 25 respectively.