Hi Sri,

We don't know if P or Q is the bigger number. With THAT idea in mind, how would you answer this question differently?

GMAT assassins aren't born, they're made,
Rich

gmattesttaker2 wrote:Hello,

Can you please assist with this:

If p and q are two consecutive positive integers, is pq a multiple of 24?

(1) p is a multiple of 8.
(2) q is an odd integer.


I am getting A


My approach:

Let the 2 consecutive integers be p(p+1)

Is: p(p+1) a multiple of 24?

1) p is a multiple of 8

Hence is 8(8+1) a multiple of 24? - Yes. Hence, suff.


2) q is an odd integer

Let q = 3. Hence, p = 2 - Is pq a multiple of 24 - No.
However as seen above when p = 8 and q = 9, pq is a multiple of 24.

Hence, in-suff.


Hence, A


Thanks for your help,
Sri

Hey Sri,

The problem with your solution is highlighted above in blue.
Statement 1 says that p is a multiple of 8, but you have let p EQUAL 8
If you had also tested p = 16, you'd find that p(p+1) = (16)(17), which is not divisible by 24.

Of course, as Rich mentioned, you have also assumed that q > p, but the question does not state this.

Cheers,
Brent

gmattesttaker2 wrote: If p and q are two consecutive positive integers, is pq a multiple of 24?

(1) p is a multiple of 8.
(2) q is an odd integer.

Target question: Is pq a multiple of 24?

Given: p and q are two consecutive positive integers

Let's head straight to . . .

Statements 1 and 2 combined
There are several values of p and q that satisfy the conditions in both statements. Here are two:
Case a: p = 8 and q = 9 (so pq = 72), in which case pq is a multiple of 24
Case b: p = 8 and q = 7 (so pq = 56), in which case pq is NOT a multiple of 24
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

----------------------------------------------------
If we assume that p and q are two consecutive positive integers AND p < q, the answer is still E

Once again, we'll head straight to . . .

Statements 1 and 2 combined
There are several values of p and q that satisfy the conditions in both statements. Here are two:
Case a: p = 8 and q = 9, in which case pq is a multiple of 24
Case b: p = 16 and q = 17, in which case pq is NOT a multiple of 24
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E


Cheers,
Brent