71. The are 20 students and they need to be allocated into 3 how many ways can this be done
1.assuming that the students are identical
2.assuming that the students are distinguishable

72. There are m pipes from 1 to m..such that tge speed at which it fills a pool alone is equal to the time taken by other m-1 pipes(not for m=1)..suppose time taken by 9 pipe is 40min when filled alone..what would be the time taken if pipe no. 12 and 13 fill together..??

73. Suppose you have a currency called miso in three denominations, 1 miso, 10misos and 50 misos. In how many ways can you pay a bill of 107 misos?
a.17 b.16 c.18 d.15 e.19

73. No of ways you can fill a 3*3 grid (with 4 corners marked as a,b,c,d) if you have 3 white and 6 black marbles ?
a) 9c3 b) 6c3 c) 9c3+6c3 d) (9c3+6c3)/3!

74. v,w,x,y,z are non negative integers each <11, then how many distinct combinations of (v,w,x,y,z) that satisfy v(11^4)+w(11^3)+x(11^2)+y(11)+z= 151001 ?

75. How many values of 'c' results in rational roots which are integer in x^2-5x+c?
a) 1 b) 3 c) 6 d) infinite

76. A square of side x is given... Joining the mid point of the sides another square is this way it is continued...what will be the perimeter of the the 9th square?

77. There are 10 letter and 10 correspondingly 10 different address if the letter are put into envelope randomly. then find the probability that exactly 9 letter will at the correct address?

78. A box contain 3 red and 2 white balls and balls are taken out one by one without replacement. So what is the probability the white balls always come at last?

79. What will be the be the unit digit when xxyyzz is divided by 1001, if x>y>z ?

80. What is the reminder when a 4 digit no p^2+17;where p is a prime no of form 6x+-1 ?