Answer
The standard divisor is 50
Work Step by Step
We can find the total patient load.
total load = 119 + 165 + 216 = 500
We can find the standard divisor.
$standard~divisor = \frac{total~load}{number~of~ doctors}$
$standard~divisor = \frac{500}{10}$
$standard~divisor = 50$
The standard divisor is 50