Answer:

Step-by-step explanation:
Given
i.e. 1 per 20cc of water
-- sample size
Required
The variance
This is calculated using:

So, we have:





Answer:
6 years old
Step-by-step explanation:
First, turn the information given in words as equations. Use variables to represent the people:
let A be Addison's age
let B be Bailey's age
let C be Christopher's age
A = 3B (Addison is 3 times as old as Bailey)
B = 2.5C (Bailey is 2.5 times as old as Christopher)
A + B + C = 66 (the sum of their ages is 66) (sum means addition)
Start with the equation for the sum of their ages (A + B + C = 66). You have other equations that can replace the variables in this equation.
A + B + C = 66
(3B) + B + C = 66 Replace A with 3B (because A = 3B)
4B + C = 66 Collect like terms (3B + B = 4B)
4(2.5C) + C = 66 Replace B with 2.5C (because B = 2.5C)
10C + C = 66 Collect like terms (10C + C = 11C)
11C = 66 Isolate "C"
11C/11 = 66/11 Divide both sides by 11 to cancel out 11 on the left side.
C = 6 Christopher's Age
Therefore Christopher is 6 years old.
I am not sure if it is A or B but it is definitely one of those because they have different y-intercepts. You have a 50/50 chance if you want to guess or you can graph it out and get an exact answer. Hope this helps!
Number 28 is 36 because if you look at the ratio on the left of it you see that it is 81:81, which would mean that 36:36.
Answer:
1836
Step-by-step explanation:
108 Times 17 is 1836