Algebra word problem

Question

some schools give professors the option of being paid 26 times a year or being paid 20 times a year. A professor said that they switched from 20 to 26 times a year, then each paycheck would be $900 less, though they would of course still make the same total amount of money over the course of the year. What is that total salary?

Answer 1

20x = 26(x-900) = 26x - 23400

6x = 23,400

x = 3,900

20x = $78,000 = annual salary