Answer:
11.4
20/100 = x/57
Step-by-step explanation:
It is perhaps simplest just to translate the given English sentence into a mathematical sentence.
... 20% ... ... of ... 57 ... is ... what number
... 20/100 ... × ... 57 .... = ... what number . . . . . . . . translation to math sentence
... 11.4 = what number . . . . . . . . carry out the multiplication
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If you're asked to write this as a proportion, you can write it like this:

You can solve this proportion by multiplying by 57 (the denominator under "what number"). Doing so gives you the same arithmetic sentence as shown above.
First, mentally add the whole numbers.
4+3+5=12
Now, look at the fractions. 1/8, 2/3, and 1/2.
2/3 is bigger than 1/2, so you can add in another whole number.
12+1=13
1/8 is tiny, and won't add a whole lot to the mix, so just leave that.
A reasonable estimate would be 13 1/8
Step-by-step explanation:
Buy 2 get 1 free only makes you want to spend more.
And the buy 2 get 1 free is a tempting deal that most people can't resist.