Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  CBSE XI  >>  Math  >>  Permutations and Combinations
0 votes

Using the digits 1,2,3,4,5,6,7,a number of 4 different digit is formed. Find How many numbers are exactly divisible by 2

$\begin{array}{1 1}(A)\;360\\(B)\;125\\(C)\;150\\(D)\;175\end{array} $

Can you answer this question?

1 Answer

0 votes
We have to look for no which ends with 2,4 or 6
The last digit has to end with 2,4,6
The other three digit no.can be formed =1,3,4,5,6,7 as the last digit is 2
Hence the no. of ways =$6P_3$
$\Rightarrow \large\frac{6!}{3!}$
$\Rightarrow \large\frac{6\times 5\times 4\times 3!}{3!}$
$\Rightarrow 120$
$\therefore$ Applying the same
We get the same for numbers ending with 4 or 6
Thus the total no of ways =$120\times 3$
$\Rightarrow 360$
Hence (A) is the correct answer.
answered May 19, 2014 by sreemathi.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App