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

How many numbers arc there between 99 and 1000 such that the digit 8 occupies the units place?

Examine the following statements:

1. All colours are pleasant.

2. Some colours are pleasant.

3. No colour is pleasant.

4. Some colours are not pleasant.

Given that statement 4 is true, what can be definitely concluded?