If 2 boys and 2 girls are to be arranged in a row so that the girls are not next to each other, how many possible arrangements are there?

A bag contains 20 balls. 8 balls are green, 7 are white and 5 are red. What is Hie minimum number of balls that must be picked up from the bag blindfolded (without replacing any of it) to be assured of picking at least one ball of each colour?

Consider the following relationships among members of a family of six persons A, B, C, D, E and F:

1. The number of males equals that of females.

2. A and F are sons of F.

3. D is the mother of two, one boy and one girl.

4. B is the son of A.

5. There is only one married couple in the family at present.

Which one of the following inferences can be drawn from the above?

P works thrice as fast as Q, whereas P and Q together can work four times as fast as R. If P, Q and R together work on a job, in what ratio should they share the earnings?

The age of Mr. X last year was the square of a number and it would be the cube of a number next year. What is the least number of years he must wait for his age to become the cube of a number again?

If for a sample data

Mean < Median < Mode

then the distribution is