21.The number of words that can be formed by taking 4 letters at a time out of the letters of the word MATHEMATICS is

22.The sides AB, BC, CA of a triangle ABC have 3, 4, and 5 interior points respectively on them. The number of triangles that can be constructed using these points as vertices is

23.Passengers are to travel by double decked bus which can accommodate 13 in the upper deck and 7 in the lower deck. The number of ways that they can be distributed if 5 refuse to sit in the upper deck and 8 refuse to sit in the lower deck is

24.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 is

25.All letters of the word AGAIN are permuted in all possible ways and the words so formed (with or without meaning )are written as in dictionary, then the 50 word is