Answer
$\dfrac{19}{125}=15.2\%$
Work Step by Step
You have to find the total number of blocks by adding the given colored blocks: $36+48+22+19=125$.
You have $125$ colored blocks and $19$ of them are purple blocks and have to find the probability of picking a purple block:
$P(P)=\dfrac{\text{number of purple blocks}}{\text{total number of blocks}}$
$P(P)=\dfrac{19}{125}=15.2\%$
