Free Practice Question
PS · Problem Solving
555-605
Number Properties
Let X be a prime number greater than 10. Define Y as Y = X + X^3 + X^5 + X^7. Which statement about Y is certainly true?
Answer Choices
Correct answer marked belowA
Y is a prime number.
B
Y is odd.
Y is even.
Correct
D
Y is divisible by 3.
E
Y is divisible by 7.
See the full step-by-step explanation
You can see the correct answer above. Sign in for free to unlock the complete worked solution.
Track your performance and improve
Get detailed analytics, unlock full explanations, and move up difficulty tiers as you practice.
Explanation
Preview
Official Explanation
Official
Consider X = 13 (as there is only one definitive answer). Then, Y = 13 + 13^3 + 13^5 + 13^7. We can analyze Y as follows: Y…
Read the full explanation
Sign in for free to see the complete step-by-step solution to this question.
Comments
Sign in to join the discussion
No comments yet
Be the first to share your thoughts and help others understand it better.
Sign in to commentWhat this question tests
What it tests
Your command of divisibility, primes, factors, parity, and how the GMAT tests properties of integers.
Common trap
Forgetting that 1 is not prime, that 0 is divisible by every integer, or that negative numbers flip your assumptions.
Details
Difficulty
555-605
Type
PS
Category