Question #47bec

Question

2035 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-31T19:40:32

$35.7%$

$0.25/70=0.357...$

$0.357xx100=35.7%$

Answer 2 · 2017-03-31T19:51:10

$35 5/7%$ Exactly

If you use decimals you do not have a precise answer

$~~35.71%$ to 2 decimal places $larr$ approximately

$color(blue)("Very important facts about percentages")$

Percent is just another fraction. The special thing about percent is that the bottom number (denominator) is fixed at 100.

The symbol % is like a unit of measurement but one where it is worth $1/100$

So as an example: 20% $->20xx%->20xx1/100=20/100$
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$color(blue)("Answering the question")$

Let the unknown value be $x$ then we have:

$25/70=x/100$

To 'get' $x$ on its own we need to 'get rid' of the 100 in $x/100$ . We do this by changing into 1 because $1xx x" gives just "x$

Multiply both sides by 100

$color(green)(25/70color(red)(xx100)" "=" "x/100color(red)(xx100))$

$color(green)(5/14color(red)(xx100) " "=" "x xx (color(red)(100))/100)$

but $100/100$ is the same as 1 giving:

$x=35 5/7$

So we have: $" "(35 5/7)/100" "=" "35 5/7xx1/100" "=" "35 5/7%$