Question

A library shelf has 6 identical mathematics books, 3 identical physics books and 4 identical chemistry books. The number of different possible arrangements of these books are

Answer 1

maths book can be arranged in 6 different ways, so 6 !
physics book can be arranged in 3 different ways, so 3 !
chemistry book can be arranged in 4 different ways, so 4 !

So answer would be 6! * 3! * 4!...

Answer 2

hm i got 103680 for that..
answer should be 60 060 i think

Answer 3

@waterineyes , @ganeshie8 ???

Answer 4

its okay i got it..
\[\frac{13!}{6!*4!*3!}\]

Answer 5

They are identical this will make the difference I guess..

Answer 6

Yes you are right @powerangers69

Well Done..

Answer 7

hmmm, yes.. this is what we do for identical cases.. @powerangers69 : great job :)

Answer 8

@Ganpat it is same as I had given you that day..

Remember taking example of your name??

Answer 9

yup.. special case :)...

thats y i called u over here :D...

Answer 10

for probability how do u know when to times or to add ?

Answer 11

if they say and than u shd multiply

If they say or , that you should add...

Answer 12

for eg: A bag has different color balls..

1. pick the ball from the such that it is bag red and blue..
Multiply

2. Pick the ball from the bag it either red or blue..
add..

Answer 13

a team of 3 boys and 3 girls is to be chosen from a group of 8 boys and 5 girls. How many idfferent teams are possible?
8C3 + or x 5C3

Answer 14

8C3 x 5C3

as the question says, from a group of 8 boys AND 5 girls..

Answer 15

and best example for the other operation (+ )

A team of 6 is to be chosen from a group of 8 boys and 5 girls. Such that at least 4 girls are included How many idfferent teams are possible?


(8C2 x 5C4 ) + (8C1 x 5C5)...

getting it ??

Answer 16

yeahh around 85% understand :)
adding the number of teams with at least 4 girls

Answer 17

ha ha.. so what stuck up in 15 % ??

Answer 18

is the answer to that queestion
\[13C6 - (8C4*5C2)\]
umm so in terms of tree diagram.. adding is like adding the number of branches on the same level while multiple is when u move along a branch

Answer 19

answer to which question ??

Answer 20

your example

Answer 21

1-4boys = atleast 4 girls?

Answer 22

what i mentioned over there is the answer..

(8C2 x 5C4 ) + (8C1 x 5C5)...

Answer 23

like ,atleast 4 guls get selected
1. 4 girls selected= (8C2 x 5C4 )
2. 5 girls r selected = (8C1 x 5C5)...

there r only 5 girls.. if it would have been more..than it would have continued.. till the point all the girls r selected or the complete team is formed...

Answer 24

yeah i get what you did just wondering if you can do using complement

Answer 25

complement ??

Answer 26

nevermind its okay..
another question
The letters of the words ‘MATHS IS EASY’ are to be arranged in a row. The number of ways this can be done if the consonants are to be together i

Answer 27

omg i did vowels.. let me try again

Answer 28

there are ll letters, excluding the spaces..

Now, A is occurring 2 times and s is occurring 3 times.. so have to divide by 2! * 3!..

also, Consonants should be together... consonants can be arrange in 7 ways so, 7!
and remaining can be arranged in 5 ways.. 5 !

So i guess, (7! * 5! ) / (2! * 3!)...