Answer:
He sold a total of 37 albums last month.
Step-by-step explanation:
Given,
Total earned money = $644
Base payment = $200
Additional payment for each album = $12
We have to find the number of albums sold by him.
Solution,
Let the number of albums be 'a'.
Total earned money is the sum of base payment and additional payment for each album multiplied with number of albums sold.
So framing in equation form, we get;
Subtracting both side by '200' using subtraction property, we get;
Now dividing both side by '12' using division property, we get;
Hence he sold a total of 37 albums last month.