For averages to be digits either both end nos are odd or both end nos are even, here we are looking for numbers between 101 and 199 since one end is 1, the other end should be 1/3/5/7/9 so we are looking for 5 such nos. 111 123 135 147 159 so for for middle no.sanjib wrote:How many three digit number between 100 and 200 have a digit that is the average of the other two digit.
Need the explanation please that how to deduce it in a succint way.
Similarly for end no since begin is with 1, for end to be an digit the middle no must be one of 1/3/5/7/9 i.e. 111, 132 153 174 195
since 111 is common we have a total of 9 such nos
