STEP - BY - STEP EXPLANATION
What to find?
The rate of commission.
Given:
To solve, we will follow the steps below:
Step 1
Define the formula that can be use in solving the given problem.

From the question;
amount earned = $6300 and total amount = $210000
Step 2
Substitute the values into the formula and simplify.



ANSWER
The rate of commission is 3 %