Question

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?

Answer 1

I found `14.4kg`

Explanation:

We can use our percentage to find it as:
`0.72/100*2,000=14.4kg`
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:
`100/0.72` has to be the same as `2,000/x`
i.e.
`100/0.72=(2,000)/x`
rearranging:
`x=0.72/100*2,000`