Answer
$\frac{1}{25}$
Work Step by Step
The table shows 3 with the AB+ blood type and 1 with the AB- blood type, so 4 ($3+1$) have type AB. The whole set of blood donors contained 100.
$\frac{4}{100}=\frac{4\div4}{100\div4}=\frac{1}{25}$
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.