Answer:
n=37
Step-by-step explanation:
Two lines intersect and create vertical angles.
The vertical angles are 
We know that vertical angles (also called vertically opposite angles) are equal. Therefore:

You can use cross product to slove this equation.
Answer:
FIVE
Step-by-step explanation:
It is -3 degrees Celsius per 1 hour. <span />
Step-by-step explanation:
as in the other problem, the table describes mutually exclusive attributes.
so, we can simply sum the numbers up to get the total number of students :
3+9+2+16 = 30 students.
so, when picking a random student, we have 30 possibilities.
now, how many of those 30 have the desired attributes (to have a brother AND a sister) ?
I see 3 in the table.
so, the probability to pick a student that has a brother and a sister is
3/30 = 1/10 = 0.1