# Math Help - Help with percentages..

1. ## Help with percentages..

Suppose I have the number 1000, I take 34% away from that which leaves me with 660..

Lets say I have the 660 and I know that 34% was removed from number x to give me that 660.. Whats the formula to get the original number(1000) given the number 660 and the 34%????

2. Originally Posted by tgreaves
Suppose I have the number 1000, I take 34% away from that which leaves me with 660..

Lets say I have the 660 and I know that 34% was removed from number x to give me that 660.. Whats the formula to get the original number(1000) given the number 660 and the 34%????
$
\frac{660\times 100}{x} = 34

$

therefore
$x= \frac{660 \times 100}{34}.....formula$

$
\frac{660\times 100}{x} = 34

$

therefore
$x= \frac{660 \times 100}{34}.....formula$
I think im missing something here..

$\frac{660 \times 100}{34}$ does not = 1000..

4. Originally Posted by tgreaves
Suppose I have the number 1000, I take 34% away from that which leaves me with 660..

Lets say I have the 660 and I know that 34% was removed from number x to give me that 660.. Whats the formula to get the original number(1000) given the number 660 and the 34%????
If you are told that $34\%$ is reduced then you are aware of the fact that the value remaining is $100\% - 34\% = 66\%$. For example, the value of reducing $1000$ by $34\%$ is the same as having $65\%$ remaining.

Given $\frac{a}{b} = c\%$ where $a$ is the value remaining, $b$ is the original value and $c\%$ is the percentage. Therefore, with manipulation it can be deduced that $b = (100 \times a) / c$.

For your example, $b = \frac{100 \times a}{c} \rightarrow x = \frac{100 \times 660}{66}$