mariah has decided to hire three workers . to determine whom she will hire , she has selected a group of 20 candidates . she plans to have one working interview with 3 of the 20 candidates every day to see how well they work together . how many days will it take her to have working interviews with all the different combinations of job candidates ?
520 . answer a
subtract(subtract(subtract(divide(divide(divide(factorial(20), factorial(subtract(20, 3))), factorial(3)), const_2), 20), 20), const_10)