Answer:
D.
Step-by-step explanation:
Set this up as a ratio with #parts of tank on top and #minutes on the bottom and then solve it as a proportion with x being the unknown number of minutes in the second ratio.

Notice the 1 in the numerator of the second ratio. This is because a whole tank is represented by 9/9 which is the same thing as 1.
Cross multiply to solve for x:

To solve for x we will multiply both sides by 9/5:

9/5 and 5/9 cancel each other out when multiplied leaving simply "x" on the left. And multiplying on the right:

which divides to 3.6 minutes
Answer:
People shopping at a local pet store
Well, I have never seen a question posed this way, but let's check it out by trial and error.
1^3 = 3
2^3 = 8
3^3 = 27 Hey! There's one. And the ones digit ends in 3.
Let's try another number that ends in 3 and see if it works as well.
13^3 = 2197 Wow. It works again. I never noticed this before, so you taught me something new.
I will test one more.
33^3 = 35937 Bingo. I think we have a winner.
Answer:
It is a function Jonny!
Step-by-step explanation:
Hello! I would say to Jonny:
Jonny! A function is a relation between two sets, in which every element of the first set (domain) is assigned only one element of the second set (codomain).
If you have serveral elements of the first set with the same corresponding element of the second set it is correct to call that relation a function.
However, if you have an element of the first set for which your relation can relate to more than one element of the second set, then Jonny, that is not a function.
In the present case, every student ID number can only be realted to a number of the set {9, 10, 11, 12}, a student cannot have more than one current grade level. Therefore, that relation is in fact a function
Answer:
x is 4
Step-by-step explanation:
Step one: Add 12x to both sides-
8x-19+12x=-12x+61+12x
20x-19=61
Step 2: add 19 to both sides
20x -19+19=61+19
20x=80
Step 3: divide both sides by 20
20x/20=80/20
x=4