What is the tens digit of the positive integer r?GmatKiss wrote:IMO: B
Let us assume that r = xyz, here tens digit is y.
We have to find the value of y.
(1) The tens digit of r/10 is 3.
r/10 = 3
r/10 = xy.z, which implies that tens digit here is x or x = 3, but there is no info about y; NOT sufficient.
(2) The hundreds digit of 10r is 6.
10r = xyz0, here hundreds digit is y, so y = 6; SUFFICIENT.
The correct answer is B.












