Question

5 HARD math problem solving questions, for math lovers?
1. John picked a bad of oranges to give to his friends. To the first of his friends, he gave half of the oranges he had and another one beside. to his second friend he gave half of the remaining oranges and another one beside. By this time, John had one orange left. How many did he start with?

2. Ben sold half his fish and half a fish to his friend Jack and still had 22 fish left. How many fish did Ben start with?

3. One pipe fills a tank in 1 hour while another pipe can fill the same tank in 2 hours. How long will it take to fil

Answer 1

John had 1 orange left. Plus the extra he gave, that makes 2.
This was half of what John had before he gave any to his 2nd friend, so he had 4.
He gave an extra one to the 1st friend, so now we are at 5.
This in turn is half of what John started out with ---> so John started with 10 oranges.

You can verify by going through the question, but this time plugging in the numbers:
John started out with a bag of 10 oranges.
He then gave his first friend 1/2 of his 10 = 5, plus 1 more = 6, leaving John with 4
Then he gave his second friend 1/2 of his 4 = 2, plus 1 more = 3, leaving John with 1