Answer: Third option
Step-by-step explanation:
For this exercise it is important to remember the following:
1. By definition, the Associative property of addition states that it does not matter how you grouped the numbers, you will always obtained the same sum.
2. The rule for the Associative property of addition is the following (given three numbers "a", "b" and "c"):

Knowing the information shown before, you can identify in the picture attached that the option that illustrates the Associative property of addition is the third one. This is:

As you can notice that you will always get the same result:

STEP 1:
find the sales tax (decimal form)
x= sales tax
Cost + (Cost * Sales Tax)= Total
plug in known numbers
$9.40 + ($9.40 * x)= $9.87
9.40 + 9.40x= 9.87
subtract 9.40 from both sides
9.40x= 0.47
divide both sides by 9.40
x= 0.47/9.40
x= 0.05 sales tax decimal form
STEP 2:
find sales tax percentage
= 0.05 * 100
or move decimal to the right two decimal places
= 5% sales tax percent form
ANSWER: The sales tax is 5% (or 0.05 in decimal form)
Hope this helps! :)
450 g in 2:13
<u>Total proportion asked for </u>=2+13=15
<u>Now comparing g with ratio, or whatever </u>
450/15=30g
Therefore 1 in ratio depicts of 30g
So final answer = 

More to know, daily bit of knowledge: The Binomial Theorem:

Answer:
C
Step-by-step explanation:
The tosses before that were all by chance, the probability is still the same. Nothing changes.