Here’s a refresher on our first ACT Challenge Question. If you haven’t had a chance to solve it yet, take a crack at it and then scroll down for the answer and explanation. No peeking!

## ACT Challenge Question #1

There are two ways to solve this problem: the “math” way and the “test prep strategy” way.

Let’s talk about the test prep strategy way first. You see, this problem is a great candidate for plugging in numbers for and and seeing what works.

Let’s try

Therefore becomes

So now we have a corresponding value for .

When , the expression in the question, , equals . So now we have the numerical answer we are looking for in the answer choices, expressed in terms of (which we determined equals .

So, plugging in for , the answer choice equivalents would be:

A. 1/1024
B. 1/19
C. 32
D. 64
E. 1024

Now let’s talk about the math way:

Using the exponent rule we know that

so we can simplify the given equation

would then be

Since we found that we can sub in for in the expression above and get our answer: C.