21. Sal and Sam are brothers. Steve is Sal's son, and 12 years younger than his uncle. Sal is twice as old as Steve.
Four years ago, Sal was the same age as Sam is now, and Sam was twice as old as his nephew. What are all the ages?

Sal is 32, Sam is 28 and Steve is 16.

22. Tony likes indigo but not blue. He likes onions but not turnips; he likes forms but not shapes. According to the same rule does he like tomatoes or avocados?

Tony likes tomatoes. He only likes words that start with prepositions.

23. A man wanted to enter an exclusive club but did not know the password that was required. He waited by the
door and listened. A club member knocked on the door and the doorman said, "twelve." The member replied, "six" and was let in. Another member
came to the door and the doorman said, "six." The member replied, "three" and was also let in. The man thought he had heard enough and walked up and
knocked on the door. The doorman said, "ten" and the man replied, "five." He was not let in. What should he have replied and why?

Three. The doorman lets in those who answer with the number that is equal to the number of letters in the word he says.

24. A snail is at the bottom of a well and wants to get out. He manages to crawl up the wall 3 feet each day, but at night he must rest (
after all that work during the day ) and so he slips back down 2 feet. If the well is 30 feet deep, How long will it take him to get out?

28 days. The snail averages 1 foot each day, so after 27 days he has reached 27 feet. On the 28th day he crawls up 3 feet during the day, but since he is now at 30 feet and out of the well he no longer slips back 2 feet.

25. A builder needs 11 pounds of sand for his pool foundation. The sand supplier has a lot of sand, two large boxes
on a balance scale, but only two weights: a 5 pound weight and a 4 pound weight. How can you measure exactly 11 pounds of sand without
removing any sand from either of the boxes during the process?

Put the 5 lb weight into one of the boxes and balance it by putting sand into the other box. Then remove the weight from the empty box and fill it with 5 lbs of sand which again balances the scale. Then put the 5 lb weight in one box and the 4 lb weight in the other and add sand to the box with the 4lb weight until it balances (that puts 6 lbs of sand into that box). Take off both weights and then place the 5 lb weight in the box that already has 6 lbs of sand (there is 11 lbs of weight on that side of the scale now.) Fill the box that has the 5 lbs of sand until it balances and you now have 11 lbs of sand in that box.

26. Examine the following:

1 + 23 - 4 + 5 - 6 + 78 + 9 = 106

Notice that the digits 1 through 9 are used in order to arrive at 106. Using 1 through 9 in order, and using only addition or subtraction,
create an equation that equals 100. There are many solutions.

Here are a few solutions: 123 + 45 - 67 + 8 - 9 = 100 or 12 - 3 - 4 + 5 - 6 + 7 + 89 = 100 or 1 + 23 - 4 + 5 + 6 + 78 - 9 = 100.

27. You have two ropes. Each takes exactly 60 minutes to burn. They are made of different material so even though they take
the same amount of time to burn, they burn at separate rates. In addition, each rope burns inconsistently.

How do you measure out exactly 45 minutes?

Take one rope and light it at both ends. At the same time, light one end of the other rope. When the first rope finishes burning, light the other end of the remaining rope. When it burns out, that's 45 minutes.

28. What are the next two letters in the following series and why?

W A T N T L I T F S _ _

A and W - The pattern is the first letter of every word in the sentence.

29. I was relaxing on a park bench one day when I noticed there were ducks in the pond. I saw two ducks in front of a duck,
two ducks behind a duck and one duck exactly in the middle of the other ducks. How many ducks were there?

30. Mary is 54 years old, and her mother is 80. How many years ago was her mother three times the age of her daughter Mary?

41 years ago, when Mary was 13 and her mother was 39.