Chemistry
posted by Ashley on .
An unknown element Q has two known isotopes: 60Q and 63Q. If the average atomic mass is 60.5 amu, what are the relative percentages of the isotopes?

There is little point in posting the same question twice within a couple of minutes.
Let the fraction of 60Q be x and therefore the fraction of 63Q is 1x.
60x +(1x)63=60.5
can you take it from here?