how many 3 digit numbers can be formed with 2 consecutive same numbers .  Choose the correct choice:
A) 160
B) 171
C) 180
D) 256
E) 352
if you fix the 2nd and 3rd position which can be done in 10 ways and 1st position can take value from 1-9 therefore total ways comes out to b  9*10= 
<gadget id="calculator"> 9*10</gadget>
<output>90</output>
90   plus   if you fix the 1st nd 2 position which can be done in 9 ways and 3rd position can take 10 values i.e from 0-9, that makes it 9*10= 
<gadget id="calculator">9*10</gadget>
<output>90</output>
90   total=90+90= 
<gadget id="calculator">90+90</gadget>
<output>180</output>
180   now minus the common part like 111,222 to 999   that is total of 9 numbers..   therefore finally 180-9= 
<gadget id="calculator">180-9</gadget>
<output>171</output>
171   ANSWER:171
<result>B</result>
how many 3 digit numbers can be formed with 2 consecutive same numbers .