I eventually solved for 729... took me around 2 minutes but need to know if there's a faster way to do this. BTW this is a repost, the original was in the wrong format.
Thanks.
OA: A
Thanks.
OA: A
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Yes, there is.
If the remainder of a number divided by 10 has to be 0, then the number has to be zero..
which means the value of 3^x + 1 must end with 0..or which means the value of 3^x must end with 9.
So, we should know the cyclicity of number 3 which is 4.
If you note the series, u can see that it is 3,9,27,81,243,729....
So, 2nd, 6th, 10th, 14th digit would all end with a value of 9.
All these informations are pre-requisites to attend this problem which would help us to solve this one within 30 seconds.
Now, look at at the two statements..
statement 1 says X = 4n + 2, where n is a positive integer...
substitute any value for n and u will find that X will end up with values like 6, 10, 14 etc...
which means 3^x will end with 9 and 3^x + 1 with 10..remainder 0...
Sufficient..
Statement 2 says X > 4...X can be any number...So statement 2 alone is insufficient..
Hence, the answer is A.
