The things of beauty

Find the number of selections of one or more things from the group of p identical things of one type, q identical things of another type, r identical things of the third type and n different things.

The things which are double of the same thing are equal to one another.

Let p be " I will marry her," and let q be " she is beautiful." Translate into symbolic form. If I will not marry her, then she is not beautiful.

Let p be " I will marry her," and let q be " she is beautiful." Translate into symbolic form. If she is not beautiful, then I will not marry her.

The number of ways in which m+n(nlem+1) different things can be arranged in a row such that no two of the n things may be together, is

Try segregating the things around you as pure substances or mixtures.

We see most of the things around us by ....................(regular reflection/diffused reflection)

A person who can see things most clearly at a distance of 10 cm . Requires spectacles to enable to him to see clearly things at a distance of 30 cm. What should be the focal length of the spectacles ?

Number of ways of selecting one or more things out of n dissimilar things are

Number of ways of selecting r consecutive things out of n things