How many factors does y have?
(1) y is the cube of an integer.
(2) y is the product of 2 distinct positive digits.
Can some experts find how it become the Best Option?
OA C
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How many factors does y have?
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Hi lheiannie07,
We're asked for the number of factors that Y has.
1) Y is the CUBE of an integer.
IF....
Y = 1, then Y has 1 factor (1)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 1 is INSUFFICIENT
2) Y is the product of 2 distinct positive digits.
IF...
Y = 2, then Y has 2 factors (1 and 2)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 2 is INSUFFICIENT
Combined, we know...
Y is a CUBE
Y is limited by Fact 2 to the product of 2 SINGLE-DIGIT integers. (for example: 8 is possible, since 8 = 2 x 4; 100 is NOT possible since you cannot get to 100 by multiplying two 1-digit numbers).
The number of possible cubes worth considering is limited: 1, 8, 27, 64, 125
1, 64 and 125 do NOT fit the 'restrictions' given by the two Facts - so we're left with just 8 and 27
IF....
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Y = 27, then Y has 4 factors (1, 3, 9 and 27)
The answer is ALWAYS 4.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
We're asked for the number of factors that Y has.
1) Y is the CUBE of an integer.
IF....
Y = 1, then Y has 1 factor (1)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 1 is INSUFFICIENT
2) Y is the product of 2 distinct positive digits.
IF...
Y = 2, then Y has 2 factors (1 and 2)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 2 is INSUFFICIENT
Combined, we know...
Y is a CUBE
Y is limited by Fact 2 to the product of 2 SINGLE-DIGIT integers. (for example: 8 is possible, since 8 = 2 x 4; 100 is NOT possible since you cannot get to 100 by multiplying two 1-digit numbers).
The number of possible cubes worth considering is limited: 1, 8, 27, 64, 125
1, 64 and 125 do NOT fit the 'restrictions' given by the two Facts - so we're left with just 8 and 27
IF....
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Y = 27, then Y has 4 factors (1, 3, 9 and 27)
The answer is ALWAYS 4.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
-
BTGmoderatorDC
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
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Thanks a lot![email protected] wrote:Hi lheiannie07,
We're asked for the number of factors that Y has.
1) Y is the CUBE of an integer.
IF....
Y = 1, then Y has 1 factor (1)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 1 is INSUFFICIENT
2) Y is the product of 2 distinct positive digits.
IF...
Y = 2, then Y has 2 factors (1 and 2)
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Fact 2 is INSUFFICIENT
Combined, we know...
Y is a CUBE
Y is limited by Fact 2 to the product of 2 SINGLE-DIGIT integers. (for example: 8 is possible, since 8 = 2 x 4; 100 is NOT possible since you cannot get to 100 by multiplying two 1-digit numbers).
The number of possible cubes worth considering is limited: 1, 8, 27, 64, 125
1, 64 and 125 do NOT fit the 'restrictions' given by the two Facts - so we're left with just 8 and 27
IF....
Y = 8, then Y has 4 factors (1, 2, 4 and 8)
Y = 27, then Y has 4 factors (1, 3, 9 and 27)
The answer is ALWAYS 4.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
