on day one , a store sold 86 cups . on each of the next d days , the company sold 50 cups . if the average daily sales of cups over this time period ( including day one ) is 53 cups , what is the value of d ?
86 + 50 d = 53 ( d + 1 ) . 3 d = 33 . d = 11 . the answer is c .
subtract(add(divide(add(add(86, 50), 53), const_3), const_1), 53)