1) IMO - A

2) IMO - C

What is the OA?

vinaynp wrote:1) Is x even?

a) x is a multiple of 6.
b) x is multiple of 5.

2) If x is a prime number, what is the value of x?

a) x < 15
b) (x-2) is a multiple of 5.


OA to follow soon

For question 1:

(1): if x is a multiple of 6, then it is definitely even. Sufficient
(2): if x is a multiple of 5, then it may or may not be even. For example, x can be 5 or 10. Insufficient.

Choose A.

For question 2:

(1): clearly insufficient.
(2): We know that x is prime, and that x - 2 is a multiple of 5.

2 - 2 = 0, and 0 is a multiple of 5.*
7 - 2 = 5, and 5 is a multiple of 5.
So, x can take multiple values. (In fact, x can take an infinite number of values). Insufficient.

Combined, we know that x is prime, that x<15, and that x - 2 is a multiple of 5. So, x can be 2 or 7.

Choose E.

*This is an important concept--it's also the concept being tested in this question. x is said to be divisible by y when the result of dividing x by y is an integer. 0 can be divided by any number leaving 0, which itself is an integer. Thus, 0 is divisible by--is a multiple of--all numbers. On the other hand, one cannot divide any number by 0, and thus 0 is not a factor of any number.

0 is:
--even
--neither positive nor negative
--a multiple of all numbers (except 0)
--not a factor of any number

Testluv wrote:

vinaynp wrote:1) Is x even?

a) x is a multiple of 6.
b) x is multiple of 5.

2) If x is a prime number, what is the value of x?

a) x < 15
b) (x-2) is a multiple of 5.


OA to follow soon

For question 1:

(1): if x is a multiple of 6, then it is definitely even. Sufficient
(2): if x is a multiple of 5, then it may or may not be even. For example, x can be 5 or 10. Insufficient.

Choose A.

For question 2:

(1): clearly insufficient.
(2): We know that x is prime, and that x - 2 is a multiple of 5.

2 - 2 = 0, and 0 is a multiple of 5.*
7 - 2 = 5, and 5 is a multiple of 5.
So, x can take multiple values. (In fact, x can take an infinite number of values). Insufficient.

Combined, we know that x is prime, that x<15, and that x - 2 is a multiple of 5. So, x can be 2 or 7.

Choose E.

*This is an important concept--it's also the concept being tested in this question. x is said to be divisible by y when the result of dividing x by y is an integer. 0 can be divided by any number leaving 0, which itself is an integer. Thus, 0 is divisible by--is a multiple of--all numbers. On the other hand, one cannot divide any number by 0, and thus 0 is not a factor of any number.

0 is:
--even
--neither positive nor negative
--a multiple of all numbers (except 0)
--not a factor of any number

Thanks. It is correct.