What is 67.5% of 80?

2 Answers
Feb 12, 2017

Answer:

#54#

Explanation:

Multiply 80 with 67.5% in decimal form, which is #67.5/100" or "0.675. #

So we now have:

#80 xx 0.675 = 54#

Feb 12, 2017

Answer:

54

Explanation:

The % symbol is like a unit of measurement that is worth #1/100 #

So # 67.5%" is the same as "67.5xx1/100 = 67.5/100#

Consider the word 'of' in 65% of 80 as being the same as multiply

As an example: 3 of 78 is the same as #78+78+78 -> 3xx78#

So 67.6% of 80 #-> 67.5%xx80 -> 67.5/100xx80#

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Let me introduce you to a trick to work this out without using a calculator.

Write as #67.5xx80/100#

#67.5xx(8xx10)/100 #

#67.5xx8/10#

8 is the same as #2xx2xx2#

First doubling of 67.5 = 135.0
Second doubling = 270
Third doubling = 540

Now we have:

#540/10 = 54#
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Check by calculator: #67.5/100xx80= 54#

#color(brown)("Sometimes the numbers do not lend themselves to this type of approach")#