math class 8

Question: Answer: ..

Question: For the post of 5 teachers, there are 23 applicants. 2 posts are reserved for S.C. candidates and there are 7 S.C. candidates among applicants. In how many ways can the selection be made? Answer: There are 23 applicants. Among this, 7 are S.C. candidates. We have to select 2 S..

A square matrix A=[a i j ] n x n is called a diagonal matrix if all the elements, except those in the leading diagonal, are zero. i.e., a i j = 0 for all i ..

Question: Find n, if P(n-1,3): P(n+1,3):: 5 : 12. Answer: n = 8 (as n cannot be a fraction..

Question: Given five different green dyes, four different blue dyes and three different red dyes, how many combinations of dyes can be chosen taking atleast one green and one blue dye? Answer: The least number of dyes that a combination can have is 2. (one blue and one green). Maximum ..

\ n = 8..

= (32.16.8.4.2)(33.31.30.18.17.15.14.13.12.11.10....3.1) = (2 5 .2 4 .2 3 .2 2 .2 1 )(33.31.30.....3.1) which is divisible by 2 1 5 . vi) (n! + 1) is not divisible by any natural number between 2 and ..

Question: A lady wants to select one cotton saree and one polyster saree from a collection of 8 cotton sarees and 11 polyster sarees. In how many ways can the lady choose the two sarees? Answer: Here, there are two events E 1 and E 2 . E 1 = Selection of one cotton saree fro..

..

..