Let's begin by listing out the information given to us:
There are four students: n = 4
Number of students to be selected: r = 2
To calculate the combination of 2 students to be chosen, we use:

Therefore, there 12 possible combinations from these
5 5/30 is the answer to the question.
Answer:
60x-80
Step-by-step explanation:
per hour is x and the fee is negative 80
Answer:
I think the answer is x is 16 and y is 20? I could be wrong tho
Step-by-step explanation:
First, subtract -7 from -1 to get 8.
Then, add the 12 and you get 16 for x.
First, subtract 7y from 9x to get 2y
Then, add 4 to get 20 for y.
I got -3.........................
-7 - 7p = 3p + 23
Move the -7p over to the right....by adding
-7 = 10p +23
Move the 23 over to the left by subtracting
-30 = 10p
divide by 10
p = -3