Data Sufficiency

77. What is the remainder when n is divided by 10?
1). The tens digit of 11^n is 4
2). The hundreds digit of 5^n is 6

OA after few explanations

The answer seems to be A

f2001290 wrote:77. What is the remainder when n is divided by 10?
1). The tens digit of 11^n is 4
2). The hundreds digit of 5^n is 6

OA after few explanations

Whats the source for this one?

You'll need properties for multiplication by 11 to solve this one -- if a number say ab1 is multiplied by 11, the units digit will be 1, tens digit will be b+1.

Now, just calculating the tens digit, we have

11^1 = 11
11^2 = 121
11^3 = x31
11^4 = x41
...
11^9 = x91
11^10 = x01
...
11^14 = x41
...

The sequence repeats and so whenever n = 4, 14, 24 ... we get the
tens digit of 11^n to be 4.

So, n/10 will always yield a remainder of 4.

2 - insufficient. After n = 4, we get alternating x125 and x625. So, we
cannot say what n is for sure.

Hence A.

Again, I'm not too sure if such questions are tested on the GMAT.