Answer:
20. 300π m³
21. 457 1/3 π cm³
Step-by-step explanation:
20. r = 10 ÷ 2 = 5
V = 5² × 12 × π = 25 × 12π=300π m³
21. r = 14 ÷ 2 = 7

V = 457 1/3 π cm³
Answer:
She went on the slide 8 times and on the roller coaster 4 times
Step-by-step explanation:
We convert each statements to a mathematical equation.
Firstly, let's represent the number of times she went on the coaster with R and the number of times on the slide with S. We know quite well she went on 12 rides. Hence the summation of both number of times yield 12.
Mathematically, R + S = 12. ........(i)
Now we also know her total wait time was 3hours. Since an hour equals 60 minutes, her total wait time would equal 180 minutes.
To get a mathematical representation for the wait time, we multiply the number of roller coaster rides by 25 and that of the slides by 10.
Mathematically, 25R + 10S = 180 .......(ii)
Here we now have two equations that we can solve simultaneously.
From equation 1 we can say R = 12 - S. We can then substitute this into equation 2 to yield the following:
25(12 - s) + 10s = 180
300 - 25s + 10s = 180
300 - 25s + 10s = 180
300 - 15s = 180
15s = 300 - 180
15s = 120
S = 120/15
S = 8
S = 8 , and R = 12 - S = 12 - 8 = 4
We will write it as a fraction in ordet to solve, that is:

We then operate as follows:

We have this, since 1 integer will be equal as a numerator divided by a denominator with equal values. Examples 1 = 2/2, 1 = 45/45, ...
Firstly, you do 90 - 42 to get the amount of brownies sold, which is 48. Then, you put 42 and 48 into a ratio like 42:48. After that, all you need to do is simplify to get 7:8.
Answer:
In order to have ran 33 miles, Bobby would have to attend <em>32 track practices.</em>
Step-by-step explanation:
Solving this problem entails of uncovering the amount of track practices Bobby must attend in order to have ran 33 miles. Start by reading the problem carefully to break down the information provided.
You can see that Bobby has already ran one mile on his own. This is important to remember for later. The problem also states that he expects to run one mile at every track practice.
Setting up an equation will help us solve. Here is how we could set up the equation:
(<em>amount of miles already ran</em> = 1) + (<em>number of track practices</em> = x) = (<em>total miles to run</em> = 33)
1 + x = 33
The equation is now in place. You can solve this, or isolate <em>'x',</em> by using the subtraction property of equality. This means we will subtract one from both sides of the equation, thus isolating the variable.
1 + x = 33
1 - 1 + x = 33 - 1
x = 32
The variable is the only term left on the left side of the equation. This means Bobby must attend track practice <em>32 times</em> in order to have ran 33 miles.