Answer:
4
Step-by-step explanation:
pythagoras theorem = a* + b* = c* ( by '*' i mean squared)
2* + b* = square root twenty
4 + b* = 20
b* = 16
b = 4
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
Answer:
Step-by-step explanation:
⊕ The slope will increase
Let's say the cost of student tickets is x and the cost of adult tickets is y. Then:
(1) 12y + 6x = 138
(2) 5y + 11x = 100
If we rearrange equation (1) we get:
12y = 138 - 6x
Now divide each side by 12:
y = 11.5 - 0.5x
We can now substitute this into equation (2):
5(11.5 - 0.5x) + 11x = 100
57.5 - 2.5x + 11x = 100
8.5x = 42.5
x = 5, therefor the cost of a student ticket is $5.00
I believe that 21 is d 27 over 17
I believe that 22 is d because 16 divided by 3.20 is 5
sorry if I am wrong
I hope this helps you