two-digit positive integer n

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two-digit positive integer n

by rsarashi » Sat Sep 02, 2017 4:36 am
What is the value of the two-digit positive integer n?

1) The sum of the digits in n is 12.

2) If the digits in n are reversed, the value of the number formed is 36 more than the value of n.

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by GMATGuruNY » Sat Sep 02, 2017 6:28 am
rsarashi wrote:What is the value of the two-digit positive integer n?

1) The sum of the digits in n is 12.

2) If the digits in n are reversed, the value of the number formed is 36 more than the value of n.
Statement 1:
Options for n:
39 or 93
48 or 84
57 or 75.
Since n can be different values, INSUFFICIENT.

Statement 2:
Let T = the TENS digit of n and U = the nonzero UNITS digit of n.
Then:
n = 10T + U.
When the digits in N are reversed, we get:
10U + T.

Since the reversed version is 36 greater than n, we get:
(10U + T) - (10T + U) = 36
9U - 9T = 36
9(U-T) = 36
U-T = 4
U = T+4.

Implication:
The units digit of n must be 4 greater than the tens digit of n.
Options for n:
15, 26, 37, 48, 59.
Since n can be different values, INSUFFICIENT.

Statements combined:
Of the options for n in Statement 2, only 48 is included among the list of options in Statement 1.
Thus, n=48.
SUFFICIENT.

The correct answer is C.
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