In a football championship, 153 matches were played . Every two teams played one match with each other. The number of teams, participating in the championship
is ______.

 

The total number of ways in which six ‘+’ and four ‘–’ signs can be arranged in a line such that no two signs ‘–’ occur together is ______.

A committee of 6 is to be chosen from 10 men and 7 women so as to contain atleast 3 men and 2 women. In how many different ways can this be done if two particular women refuse to serve on the same committee.

A box contains 2 white balls, 3 black balls and 4 red balls. The number of ways  threeballs be drawn from the box if at least one black ball is to be included in the draw is ______.

Three letters can be posted in five letterboxes in 3^5 ways.

In a steamer there are stalls for 12 animals, and there are horses, cows and calves (not less than 12 each) ready to be shipped. They can be loaded in 3^12  ways.

If some or all of n objects are taken at a time, the number of combinations
is 2^n–1.

There will be only 24 selections containing at least one red ball out of a bag containing 4 red and 5 black balls. It is being given that the balls of the same colour are identical.

A candidate is required to answer 7 questions out of 12 questions which are divided into two groups, each containing 6 questions. He is not permitted to attempt more than 5 questions from either group. He can choose the seven questions in 650 ways.

Which of the following gas has highest contribution in global warming?

1) Carbon-di-oxide

2) Chlorofluorocarbon

3) Nitro us oxide

4) Methane

Who was the father of Indian Space Programme?

1) Dr. Vikram Ambalal Sarabhai

2) Dr. Satish Dhawan

3) Dr. Homi J. Bhabha

4) Dr. Krishnaswami Kasturirangan