From a number of apples, a man sells half the number of existing apples plus 1 to the first customer, sells $\frac{1}{3}$ 3rd of the remaining apples plus 1 to the second customer and $\frac{1}{5}$ th 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 train starts from station A with some passengers. At station B, 10% of the passengers get down and 100 passengers get in. At station C, 50% get down and 25 get in. At station D, 50% get down and 50 get in making the total number of passengers 200. How many passengers did board the train at station A?

A farmer sold a cow and an ox for Tk. 80,000 and got a profit of 20% on the cow and 25% on the ox. If he sells the cow and the ox for Tk. 82,000 he gets a profit of 25% on the cow and 20% on the ox. Find the individual cost price of the cow and ox.