How many integers between 1000 and 10000 have
no digits other than 4, 5 or 6?  Answers
A) 91 B) 51 C) 81 D) 71 E) 61
Any number between 1,000 and 10,000 is of 4 digits. The unit’s place can be filled up by 4,5 or 6, that is, in 3 ways.   Similarly, the ten’s place can be filled up by 4 or 5 or 6, that is in 3 ways. The hundred’s place can be filled up by 4, 5 or 6, that is in 3 ways and the thousand’s place can.be filled up by 4 or 5 or 6, that is, in 3 ways.   Hence the required numbers = 3 x 3 x 3 x 3 = 81   ANSWER:81
<result>C</result>
How many integers between 1000 and 10000 have
no digits other than 4, 5 or 6?