Answer
$x_{296_{Wt}}= 0.72$
$x_{297_{Wt}}= 0.04$
$x_{298_{Wt}}=0.24$
Work Step by Step
To calculate the natural abundance of each of Wt isotope we need to divide the number of atoms of each isotope in the sample with the total number of atoms in the sample (50).
$x_{296_{Wt}}= \frac{N_{296_{Wt}}}{N_{total}}= \frac{36}{50}= 0.72$
$x_{297_{Wt}}= \frac{N_{297_{Wt}}}{N_{total}}= \frac{2}{50}= 0.04$
$x_{298_{Wt}}= \frac{N_{298_{Wt}}}{N_{total}}= \frac{12}{50}= 0.24$
