The sum of the first five prime numbers is: 

Find the number that does not belong to the group.

The sum of the first n odd natural numbers is:

How many ways can 180 be expressed as a product of two factors?

On 8th Dec, 2007, Saturday falls. What day of the week was it on 8th Dec, 2006?

Find the number that does not follow the pattern in the given sequence:

8, 27, 64, 100, 125, 216, 343

 The sum of the digits of a two-digit number is 12. The difference between the digits is 6. Find the number? 

In how many different ways can the letters of the word 'LEADING' be arranged such that the vowels (E, A, I) always come together?

 A trekking group is to be formed having 6 members. They are to be selected from 3 girls, 4 boys and 5 teachers. In how many ways can the group be formed so that there are 3 teachers and 3 boys or 2 girls and 4 teachers?
 

The cost price of 3 varieties of mangoes, namely X, Y, and Z, is Rs. 20/kg, Rs. 40/kg, and Rs. 50/kg, respectively. Find the selling price of one kg of mango in which these three varieties of mangoes are mixed in the ratio of 2 : 3 : 5, such that there is a net profit of 20%.