Question #75b7f

2 Answers
Nov 30, 2016

Answer:

60 books were donated.

Explanation:

What we are looking for is:

48 is 80% of what?

In mathematics "is" means "#=#".

"Percent" or "%" means "out of 100" or "per 100", Therefore 80% can be written as #80/100#.

When dealing with percents the word "of" means "times" or "to multiply".

And we can call "what" #n#.

So putting this altogether gives:

#48 = 80/100 *xx n#

Solving for #n# gives:

#100/80 xx 48 = 100/80 xx 80/100 xx n#

#4800/80 = 8000/8000 x n#

#60 = n#

Nov 30, 2016

Answer:

The count of donated books was 60

Explanation:

The symbol % is a unite of measurement worth #1/100#

So 80% #-> 80/100#

Let the total count of books donated be #x#
Given that the count sold is 48
Given that the percentage sold is 80%

#80/100xx x = 48#

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If you multiply #80/100" by " 100/80# you turn it into 1

So this is:

#80/100xx100/80 = (80xx100)/(100xx80) = (100xx80)/(100xx80) =100/100xx80/80 =1xx1#

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Multiply both sides by #100/80#

#1xxx= 4800/80 = 60#

#x=60#