Question #b3ab8

2 Answers
Sep 22, 2017

~~$896.4

Explanation:

Let the number be x
$645.40=72%xx x
72%xx x=$645.40
1%xx x=$645.40-:72
~~$8.963888...

100%xx x=$8.963888...xx100
=896.3888...
~~896.4

Sep 22, 2017

x = $896 7/18 as an exact value

x=$896.39 as an approximate value

Explanation:

The sign or symbol of % is like a unit of measurement but one that is worth 1/100

So 1/100 and % are interchangeable.

The word 'of' is a bit like counting. 2 of apples ->2xx"apples"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let the unknown value of dollars be x

So 72%" of "x is the same as 72%xx x

Then we have 72/100xx x =$645.40

Multiply both sides by 100/72 (turns the 72/100 on the left into 1)

72/100xx100/72xx x =100/72xx$645.40

72/72xx100/100xx x =100/72xx$645.40

1xx1xx x = $896 7/18 as an exact value

x=$896.39 as an approximate value