10610C3 * 9!2!3!4! * 3!
10C3 selection of 3 floors
9!2!3!4! distribution of 9persons in 3 different groups.
I really dont think the 3! should be der since the distribution of 9 persons contains the no of permutations as well
Q1.
9 persons enter a lift from the ground floor of a building which stops at 10 floors exulding the ground floor ,if its known that persons will leave in groups of 2,3,4 in different floors ..In how many ways can this happen
ANS 907200
Q2.
in how many ways 11 diff. books can be parcelled into 4 packets so that the three of the packets contain 3 books each and one has 2 books, if all packets have same destination ?
ANS 11!/(3!)42
also some one tell me whats the method of ficticious pratition in P&C.
whats the trick to find ans in questions like this
coeff of x4 in (1+x+x2+x3)4
-
UP 0 DOWN 0 0 4
4 Answers
106
1ans 2)
no. of ways of distribution is
11!3!3!3!2!*13!
= 11!3!4*2!
the additional 1/3! term comes beacuse of the the three groups carrying same no. of objects.
1a particle of specific charge alpha starts moving from the origin under the action of electric field Eoi cap & magnetic field Bo k cap. its velocity at (xo , o, 0) is (4icap -3icap). the value of xo is -?
1Thanks to both of u BUT plz tell me whats methof of ficticious partition
plz