What is the units digit of a^36?
a) a^2 has 9 as the units digit
b) a^3 has 3 has the units digit
IMO:D
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HeyArnold
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(1) a^2 has a units digit of 9
charting out all of the squares of 1 - 9
either 3 or 7 when squared has a units digit of 9
Insufficient
(2) a ^ 3 has a units digit of 3
charting out all of the cubes 1 - 9
only 7 has a units digit of 3
Sufficient
IMO B
charting out all of the squares of 1 - 9
either 3 or 7 when squared has a units digit of 9
Insufficient
(2) a ^ 3 has a units digit of 3
charting out all of the cubes 1 - 9
only 7 has a units digit of 3
Sufficient
IMO B
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Brent@GMATPrepNow
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Statement 1: a^2 has 9 as the units digitGmatKiss wrote:What is the units digit of a^36?
a) a^2 has 9 as the units digit
b) a^3 has 3 has the units digit
IMO:D
Since a^36 = (a^2)^18, we could find the units of a^36
SUFFICIENT
Statement 2: a^3 has 3 as the units digit
Since a^36 = (a^3)^12, we could find the units of a^36
SUFFICIENT
Answer: D
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
