P&C signs

Find the total no. of ways in which 6 "+" and 4 "-" signs can be arranged in a line such that no 2 -ve signs occur together.

Ans : 7C4 = 35

Why is it not : 6! x 7P4

4 Answers

11
virang1 Jhaveri ·

I think so they considered each + to be different which is wrong

62
Lokesh Verma ·

the answer is correct

no of ways to arrange 6 + signs in a row is 1... because all + signs are teh same

now you have to insert 4 - signs in 7 gaps...

hence 7C4

1
RAY ·

yes...right:)...,,,,,,abheek since + are all same and - are all same so

(6! x 7P4) /(6! x 4!) which is same as the answer

1
Bicchuram Aveek ·

Thnx

Your Answer

Close [X]