How many 5 digit telephone numbers can be constructed using the digits 0 to 9, if each number starts with 67 and no digit appears more than once ?

Answer

96

Explanation

Denoting `A_(1),B_(1),A_(2) and B_2` for their taking out the ball, a chart is made to denote the winner.

`therefore`Total number of ways in which the game can be won when A starts the game =36+36+18+6=96.