ANSWER
The percentage decrease is 10.4%.
EXPLANATION
To calculate percentage decrease, use the formula,
Percentage decrease
Yesterday the price of coffee was 2.40. This is the old price.
Today the price is 2.15. This is the new price.
To the nearest tenth, we have:
Therefore the percentage decrease is 10.4%.
<h3>Answer: Commutative Property (choice C)</h3>
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Explanation:
Here are all of the justifications for each step
- Step 1. None needed. This is the original expression
- Step 2. Distributive property
- Step 3. Multiply (the 3 and 5 multiply to 15)
- Step 4. Commutative property. Specifically, this is the commutative property of addition which allows us to add any two numbers in any order we want. In this case, the -15 and 4x terms swap places.
- Step 5. Associative property. The parenthesis group the first two terms away from the third term.
- Step 6. Combine like terms. Both 3x and 4x have an x only so they are like terms that combine to 7x. You can think of it as 3+4 = 7, then you just tack an x onto everything to get 3x+4x = 7x.
For this case we have the following equation:
Q = Av
Where the area is given by:
A = pi * r ^ 2
A = pi * (d / 2) ^ 2
A = (pi / 4) * d ^ 2
Substituting we have:
Q = ((pi / 4) * d ^ 2) v
From here, we clear the diameter:
d = root ((4 / pi) * (Q / v))
Substituting values we have:
d = root ((4 / pi) * (50/600))
d = 0.36 feet
Answer:
The diameter of a pipe that allows a maximum flow of 50ft ^ 3 / min of water flowing at a velocity of 600ft / min is:
d = 0.36 feet
7 is 1/4 of 28, so 7 is 25% of 28.
The drop from 28 to 7 is a drop of 21.
21 is 3 times 7, so 21 is 3 times 25%.
Answer: It is a 75% decrease.
