sachindia wrote:How do you calculate the LCM of fractions?

eg lcm of 1/6 and 1/3 =?

Statement 1 says, "the least common denominator of x/y and 1/3 is 6"
This is the same as saying "the LCM of y and 3 is 6"

Example: The least common denominator of 3/10 and 7/15 is 30. In other words, to add 3/10 and 7/15, we'd need to first rewrite them with common denominators of 30 (i.e., 3/10 + 7/15 = 9/30 + 14/30 = 23/30). Similarly, the LCM of 10 and 15 is 30.

Cheers,
Brent

sachindia wrote:In the fraction x/y, where x and y are positive integers, what is the value of y?

(1) The least common denominator of x/y and 1/3 is 6
(2) x=1

Target question: What is the value of y

Statement 1: The least common denominator of x/y and 1/3 is 6
In other words, the least common multiple (LCM) of y and 3 is 6
This means that y can equal 2 or y can equal 6
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: x=1
There are several values of x and y that meet this condition. Here are two.
Case a: x = 1 and y = 29573584
Case b: x = 1 and y = 2
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined:
There are still 2 sets of values for x and y that meet both conditions:
Case a: x = 1 and y = 2
Case b: x = 1 and y = 6
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent