Twenty-eight games were played in a football tournament with each team playing once against each other. How many teams were there?

If there are 12 persons in a party, and if each two of them shake hands with each other, how many handshake happen in the party?

Ten persons numbered 1, 2,.....,10 play a chess tournament, each player against every other player exactly one game. It is known that no game ends in a draw. If w_1, w_2,..... , w_(10) are the number of games won by players 1, 2,.....,10 respectively, and l_1, l_2,............., l_(10) are the number of games lost by the players 1, 2,.....,10 respectively, then a. sumw_i=suml_i=45 b. w_i+1_i=9 c. sumw l_1^2=81+suml_1^2 d. sumw_i^2=suml_i^2

Forty team play a tournament. Each team plays every other team just once. Each game results in a win for one team. If each team has a 50% chance of winning each game, the probability that the end of the tournament, every team has won a different number of games is a. 1//780 b. 40 !//2^(780) c. 40 !//2^(780) d. none of these

An object is held between two plane parallel mirrors inclined at 45^@ to each other. How many images do you expect to see?

In a class of 35 students, 24 like to play cricket and 16 like to play football. Also, each student likes to play at least one of the two games. How many students like to play both cricket and football ?

During meiosis, the alleles of the parental pair separate or segragate from each other. How many allele(s) are then transmitted to a gamete

Find the number of positive integers, which can be formed by using any number of digits from 0, 1, 2, 3, 4, 5 but using each digit not more than once in each number. How many of these integers are greater than 3000? What happened when repetition is allowed?

12 cells each having the same emf are connected in series and are kept in a closed box. Some of the cells are wrongly connected. This battery is connected in series with an ammeter and two similar cells . The current is 3A when the two cells aid the battery and is 2A when the cells and the battery oppose each other. How many cells in the battery are wrongly connected?

In a class tournament, all participants were to plan different game with one another. Two players fell ill after having played three games each. If the total number of games played in the tournament is equal to 84, the total number of participants in the beginning was equal to a. 10 b. 15 c. 12 d. 14

The members of a chess club took part in a round robin competition in which each player plays with other once. All members scored the same number of points, except four juniors whose total score ere 17.5. How many members were there in the club? Assume that for each win a player scores 1 point, 1/2 for a draw, and zero for losing.