The average atomic mass of a sample of an element X is 16.2 `mu`. What is the percentage of each isotope `overset(18)underset(8)X` and `overset(18)underset(8)X` in the sample?

Explanation

Let the percentage of X-16 isotope =x
The percentage of X-18 isotope =(100-x)
From the information the average atoic mass of the element X is = `(x xx16)/(100)+((100-x)xx18)/(100)`
But the given atomic mass of the element X=16.2 u
`(x xx16)/(100)+((100-0x)xx18)/(100)`
16x+1800-18x=16.2`xx`100=1620
-2x=1620-1800=-180
x=`180//2`=90
Percentage of X-16 isotope =90
Percentage of X-18 isotope =10