In how many ways 2 students can be chosen from the class of 20 students?

A committee of 5 members is to be formed out of 3 trainees, 4 professors and 6 research associates. In how many differen…

Three gentlemen and three ladies are candidates for two vacancies. A voter has to vote for two candidates. In how many w…

The number of ways which a mixed double tennis game can be arranged amongst 9 married couples if no husband and wife pla…

In how many ways can 15 people be seated around two round tables with seating capacities of 7 and 8 people?

How many alphabets need to be there in a language if one were to make 1 million distinct 3 digit initials using the alph…

In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?

A class photograph has to be taken. The front row consists of 6 girls who are sitting. 20 boys are standing behind. The …