Consider a positive integer Y that, when divided by 9, leaves a remainder of 4. Which of the following statements must be true?
I. Y is even
II. Y cannot be a prime number
III. (Y + 5) divided by 9 has a remainder of 0.
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good question
Good question
thanks, helpful explanation. the 'must be true' wording is what got me — I kept picking numbers that made I true by accident lol
same here! I tried Y=4 first and thought 'oh its even' but then Y=13 broke it. classic trap.
this one felt pretty easy honestly, sub-505 makes sense. III is straightforward once you realize you just add the remainders
tiny tip for these remainder questions: write Y = 9k + 4 right away. it makes all three statements super quick to check.
this is the way. saved me so much time on test day
What it tests
Your understanding of divisibility rules, least common multiples, and greatest common factors.
Common trap
Forgetting that 1 is not prime and that every integer divides 0.