What is the tens' digit R of the sum of the first 40 terms of 1, 11, 111, 1111, 11111, 111111, ...?	Choose the correct choice from the following options
A) R=2  B) R=3  C) R=4  D) 8  E) 9
All of the first 40 terms have 1 at the units place.   Except the first term, the tens digit of all the remaining 39 terms is 1.   So now if you do the addition   1 1   1 1   . . .   . . .   . . .   1 1   0 1   3 0   Answer is R=3
<result>B</result>
What is the tens' digit R of the sum of the first 40 terms of 1, 11, 111, 1111, 11111, 111111, ...?