Answer:
A. 1562 numbers , B. 130 numbers
Step-by-step explanation:
<u>A)</u> Using same digit again
1 digit nos = 2 ( ie 4 , 6 )
2 digit nos = 5 (ie any no) x 2 ( ie 4 ,6 )
Similarly
3 digit nos = 5 x 5 x 2
4 digit nos = 5 x 5 x 5 x 2
5 digit nos = 5 x 5 x 5 x 5 x 2
Adding all 5 equations
Total = 2 + 10 + 50 + 250 + 1250 = 1562
<u>B)</u> Cant use a digit more than once
1 digit nos = 2 ( ie 4 , 6 )
2 digit nos = 4 ( ie any no other than 4 or 6) x 2 ( ie 4 , 6 )
Similarly
3 digit nos = 4 x 3 x 2
4 digit nos = 4 x 3 x 2 x 2
5 digit nos = 4 x 3 x 2 x 1 x 2
Adding all five equations
Total = 2 + 8 + 24 + 48 + 48 = 130
