In a class of 100 students, the average weight is 30 kg. If the average weight of the girls is 24 kg and that of the boys is 32 kg, then what is the number of girls in the class?

Consider the following statements in respect of two integers p and q (both > 1) which are relatively prime:

1) Both p and q may be prime numbers.

2) Both p and q may be composite numbers

3) one of p and q may be prime and the other composite.

Which of the above statements are correct?

A plane is going in circles around an airport. The plane takes 3 minutes to complete one round. The angle of elevation of the plane from a point P on the ground at time t seconds is equal to that at time (t + 30) seconds. At time (t + x) seconds, the plane flies vertically above the point P. What is x equal to?

x, y and z are three numbers such that x is 30% of z and y is 40% of z. If x is p% of y, then what is the value of p?

For x = 462+3, what is the value of x+22x-22+x+23x-23

Suppose n is a positive integer such that (n2+ 48) is a perfect square. What is the number of such n?

What is the unit place digit in the expansion of  773?

In a certain town of population size 1,00,000 three types of newspapers (I, II and III) are available. The percentages of the people in the town who read these papers are as follows:

What is the number of people who do not read any of these three newspapers?