241. If in a group of n distinct objects, the number of arrangements of 4 objects is 12 times the number of arrangements of 2 objects, then the number of objects is
242. How many 10 digits numbers can be written by using the digits 1and 2
243. In how much time will Rs 3000 amount to Rs 3993 at 40% p.a compounded quarterly.
244. The term without x in the expansion ( 2x – 1/2x2 )12 is
245. Using binomial theorem expansion of ( 3x + 2y)4
81x4 +216x3 y + 216x2y2 + 96xy3 + 16y4
246. A natural number x is chosen at random from the first one hundred natural numbers. What is the probability that (x + 100/x) > 50
247. The number of positive integral solution of abc = 30 is
248. Solve 2a -b = 0
b +c +2d =100
a +2b +2c =60
-a +c -d =-10
249. Solve a +b +c = 0
12a +2b -3c = 5
3a +4b +c = -4
250. A= [aij] mxn is a square matrix, if