Mathematics Doubt

Math

Math

by Ashish Ranjan -
Number of replies: 2

 (i) and (ii) please solve and explain i see solution but not satisfied

13 words

In reply to Ashish Ranjan

Re: Math

by Hitesh Garg -
For (i)
There are total 5 different letters A,L,H,B,D
First select 4 letters in 5C4 ways and then arrange those 4 letters to form s word in 4! Ways.
Hence, 5C4 × 4! = 120 Ans

38 words

In reply to Ashish Ranjan

Re: Math

by Hitesh Garg -
For (ii)
For two same letters, we can either take A or L. So, two ways to select the Repeated letter AA or LL...
Now, after selecting a repeated letter, we need two different letters, and we are left with 4 different type of letters out of 5 different letters (A,L,H,B,D). Out of which, we need only two which can be selected in 4C2 ways.
And then 4 letter words containing two same letters and 2 different letters can be formed in 4!/2! Ways.
Hence 2×4C2×4!/2! = 144 Answer

96 words