Question

How many different 9 digit numbers can be formed from the number 112226677 by rearranging its digits so that the odd digits occupy even positions?

Options

• 16

• 36

• 60

• 180

Answer 1

60

Explanation:

There are 4 odd digits: 1, 1, 7, 7, and 4 even places. So, odd digits can occupy even places in `(4!)/(2!2!)` ways.

The remaining 5 places can be filled in `(5!)/(2!3!)` ways.

∴ Required no. of 9 digit numbers = `(4!)/(2!2!) xx (5!)/(2!3!)` = 60