Answer
7.5% and 92.5%
Work Step by Step
To solve this question, you need to set up an algebra equation. Set the percentage (natural abundance) of one isotope equal to x (decimal format), and the other equal to 1-x. You will end up with something like this: $6.0151x+7.0160(1-x)=6.941$ or $6.0151(1-x)+7.0160(x)=6.941$. Then solve for x. If you used the first equation, your answer for x will be the number of Lithium-6 isotopes, and if you solved for the second equation your answer for x will be the number of Lithium-7 isotopes. Using your value for x, subtract it from one to get the other isotope's natural abundance. Afterward, make sure to round to the desired number of significant digits and to convert it to percentage form.
