There are 13 girls and 4 more students that are boys that made an A grade. Thus there are 13+4=17 students that are either girls or A students.
The probability of choosing a girl or A student is 17/30.
Answer:

Step-by-step explanation:
Let c represents child bikes and a represents adult bikes.
Given : Each child bike requires 4 hours to build and 4 hours to test. Each adult bike requires 6 hours to build and 4 hours to test.
With the number of workers, the company is able to have up to 120 hours of building time and 100 hours of testing time for a week.
Then, the required system of inequality :-

If company make 10 child bikes and 12 adult bikes in the week.
Then Put c=10 and a=12 bikes in (1) and (2).
⇒Bike order meets the restrictions
⇒Bike order meets the restrictions
Hence, the system of inequality best explains whether the company can build 10 child bikes and 12 adult bikes in the week.

Since the measure of angle
is 
The measure of its reference angle = 
=
Now we have to compute the value of 


The value of (
) lies in the fourth quadrant. In fourth quadrant, the value of tan is always negative.
So, 

= -1.