Find all solutions to the equation. cos x = -1/2

 ^^

Step-by-step explanation:

You didn't add the range. I'll use (0<x<2π)

cosx = -1/2

x=-cos-¹(1/2)

x= -60°

Cosine is negative in the second and 3rd quadrants

180-x Second quadrant

x+180 3rd quadrant

So

Our answer

180-(-60)=240° or 4π/3 second quad

180+(-60) = 120° or 2π/3 3rd quad

Option B

4.72%

Step-by-step explanation:

We know that the total number of couples surveyed was 1250

Now identify the lowest frequency and divide it by the total of couples surveyed

The lowest frequency is that corresponding to 5 children or more.

The percentage is:

Only 4.72% of couples surveyed have 5 children or more

The answer is the option B