Answer
Please see the work below.
Work Step by Step
We know that the nulcide symbol for potassium is given as $K^{39}_{19}$
for calcium $Ca^{40}_{20}$
the equation for beta emission is given as
$K^{39}_{19}\rightarrow Ca+^0_{-1}e$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.