Question 2
If P and Q are positive integers, is the product 3PQ divisible by 2?
- 6Q3 + 2 is an even number
- P + 8Q2 is a prime number
Correct Answer
B
Solution
Steps 1 & 2: Understand Question and Draw Inferences
3PQ is divisible by 2, if:
- 3PQ is even
–> PQ is even (Odd term 3 plays no role in the even-odd nature of product 3PQ)
–> P is even (Power doesn’t impact the even-odd nature of a term)
So, to answer the question we need to find if P is even
Step 3: Analyze Statement 1
6Q3 + 2 is an even number
Not Sufficient. We do not know if P is even or odd
Step 4: Analyze Statement 2
P + 8Q2 is a prime number
All the prime numbers except 2 are odd
–> As Q ≠0, P + 8Q2> 2 (Given: Q is a positive integer => Q >0)
–> P + 8Q2 is always odd
8Q2 is always even
–> P must be odd (Odd + Even = Odd)
Sufficient.
Step 5: Analyze Both Statements Together (if needed)
We get a unique answer in step 4, so this step is not required
Answer: Option (B)