# Naturally occurring uranium contains 0.72 percent of the isotope uranium-235. What is the mass of uranium-235 in 2,000 kg of naturally-occurring uranium?

Mar 9, 2016

I found $14.4 k g$

#### Explanation:

We can use our percentage to find it as:
$\frac{0.72}{100} \cdot 2 , 000 = 14.4 k g$
Percentage represents a fraction of $100$ so we can say that:
if in $100$ we have $0.72$ then in $2 , 000$ we'll have $x$; or using fractions:
$\frac{100}{0.72}$ has to be the same as $2 , \frac{000}{x}$
i.e.
$\frac{100}{0.72} = \frac{2 , 000}{x}$
rearranging:
$x = \frac{0.72}{100} \cdot 2 , 000$