Top two questions are already proven correct. Is the last one correct or did i do something wrong?

Which statement shows that 6.24 is a rational number? a. 6.24 = 6.242424 b. 6.24 = 6.24 c. 6.24 = 68⁄33 d. 6.24 = 66⁄25

Calculate the effective quarterly compound interest rate equivalent to a 1% of monthly compound interest rate.

You are a male who just graduated from college with a bachelor's degree. you have a job paying $50,780.00/yr. a. how does your salary compare to the yearly median earnings for a male with a bachelor's degree? b. what is the difference between the yearly median earnings for a male with a bachelor's degree compared to a male who does not attend college after earning a high school diploma?