To calculate the monthly salary from a pay scale, you need to take into account the base pay and any additional grade pay. For the pay scale of 5200-20200 with a grade pay of 2400, the monthly salary can be determined by adding the base pay and the grade pay together.
In this case, the base pay range is from 5200 to 20200, and the grade pay is 2400. To find the monthly salary, you would add the base pay of 5200 to the grade pay of 2400, resulting in a total monthly salary of 7600. So, for the pay scale 5200-20200 with a grade pay of 2400, the monthly salary would be 7600.