Test 5, Section 4, Questions 25 and 28. How do you get to the answers?

In the future, please ask only one question per submission. I know that seems like a random request, but it makes the linking I do on the Official Test post guide easier on my end. 🙂

#25: More than 20% of all participants (all 300 of them) chose the first picture. In the first group of 150, 36 chose the first picture, and in the second group of 150, p chose the first picture; therefore, 36 + p chose the first picture overall. 36 + p must therefore be greater than 20% of 300. Translate that to math:

Rearrange a tiny bit and you have choice D:

#28: From the graph shown, you can see that the slope of function f is . The fastest way to get that is to count the rise and the run from (0, 3) to (2, 4). That’s all you need from the graph.

From there you’re told that the slope of g is 4 times the slope of f, so the slope of g must be 2. You’re also told that g goes through (0, –4), which means its y-intercept is –4! You know enough to write the slope-intercept equation of g:

From there, all you need to do is solve for :