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Q)

# Using the digits 1,2,3,4,5,6,7,a number of 4 different digit is formed.Find (c) How many numbers are exactly divisible by 25

$\begin{array}{1 1}(A)\;40\\(B)\;25\\(C)\;50\\(D)\;75\end{array}$

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A)
Thus the last two digit should be 25 or 75 for other 2 digit no. we have =$5P_2$
$\Rightarrow \large\frac{5!}{3!}$
$\Rightarrow \large\frac{5\times 4\times 3!}{3!}$
$\Rightarrow 20$
$\Rightarrow 40$