From a number of apples, a man sells half the number of existing apples plus 1 to the first customer, sells `1/3r d` of the remaining apples plus 1 to the second customer and `1/5t h` of the remaining apples plus 1 to the third customer. He then finds that he has 3 apples left. How many apples did he have originally? (a) 15 (b) 18 (c) 20 (d) 25