If m = abc, then the units digit of m is equal to the units digit of the following product:rainmaker wrote:Please explain your answer:
If (243)^x(463)^y = n, where x and y are positive integers, what is the units digit of n?
(1) x + y = 7
(2) x = 4
(units digit of a)(units digit of b)(units digit of c).
Since we are concerned only about the units digits, the question stem above can be rephrased as follows:
If (3^x)(3^y) = n, where x and y are positive integers, what is the units digit of n?
Simplfying the question stem, we get:
n = (3^x)(3^y)
n = 3^(x+y).
To determine the units digit of n, we need to know the value of x+y.
Final rephrase: What is the value of x+y?
Statement 1: x+y = 7
SUFFICIENT.
Statement 2: x=4
INSUFFICIENT.
The correct answer is A.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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