You can either approach this problem with number theory or plugging in. Given the time restrictions on the test plugging in will likely be quicker.
For statement one, plug in a value that makes the statement true. For example we can make x = 2 since $$9\cdot2^2 = 36$$
Since 2 is an even number, the answer to the question is yes. Plug in again to see if you always get yes. For example try x = 3. What you find is that you can't plug in that number because it doesn't satisfy the statement $$9\cdot3^2=81$$ so it is not divisible by 4.
What you will find is the only numbers that work with statement one are even numbers. So you will consistently get an answer of yes. Statement 1 is sufficient. Narrow your choice to A and D.
Now plug in values that make statement two true. For example x = 2 since 3(2) + 2 = 8, which is divisible by 8. Again we have an even number so the answer to the question is yes. Plug in again to see if you always get yes. For example try x = 3. Again 3 doesn't work because 3(3) + 2 = 11 and that's not divisible by 8. Again you will find only even numbers satisfy statement two. So you will consistently get an answer of yes. Statement two is sufficient. The answer is
D.
Take care,
Sionainn Marcoux
BA - Stanford University, MPP - Harvard University
Instructor, tutor for Princeton Review and Airbnb host
In other words a blend of Jamie Escalante from Stand and Deliver, Julie from The Love Boat, and Schneider the Super from One Day at a Time.
