Since you know that PQ=RQ, you have an equilateral triangle. This makes things very simple.
Angle R should be the same as angle P.
A triangle is equal to 180 degrees.
Add angles P and R. Subtract 180 from the answer you got. That will give you 2a. a divided by 2 will give you a.
Or, since there are two right triangles, you can add 47 and 90. Subtract 180 from that and you will get a.
We're going to be using combination since this question is asking how many different combinations of 10 people can be selected from a set of 23.
We would only use permutation if the order of the people in the committee mattered, which it seems it doesn't.
Formula for combination:

Where
represents the number of objects/people in the set and
represents the number of objects/people being chosen from the set
There are 23 people in the set and 10 people being chosen from the set


Usually I would prefer solving such fractions by hand instead of a calculator, but factorials can result in large numbers and there is too much multiplication. Using a calculator, we get

Thus, there are 1,144,066 different 10 person committees that can be selected from a pool of 23 people. Let me know if you need any clarifications, thanks!
~ Padoru
The nearest tenth would be 10.1
Parenthises
Exponent
Multiply
Divide
Add
Subtract
The answer is true because it comes before subtraction in the phrase PEMDAS.
You will need to set equations to solve for x and y coordinate.
(2+x)/2=4
2+x=8
x=6
(6+y)/2=10
6+y=20
y=14
The answer is A. (6,14)