Riddle: The head of a whale is six feet long; his tail is as long as his head and half his body, and his body is half of his whole length. How long is the whale?
Answer: Forty-eight feet.
Riddle: Place three piles of matches on a table, one with 11 matches, the second with 7, and the third with 6. You are to move matches so that each pile holds 8 matches. You may add to any pile only as many matches as it already contains. All the matches must come from one other pile. For example, if a pile holds 6 matches, you may add 6 to it, no more or less.
You have three moves. How can you do it?
Answer: First pile to second; second to third; third to first:
| Pile | Initial number | First move | Second move | Third move |
| First | 11 | 11-7=4 | 4 | 4+4=8 |
| Second | 7 | 7+7=14 | 14-6=8 | 8 |
| Third | 6 | 6 | 6+6=12 | 12-4=8 |
Riddle: Jim was examining an angle measuring 14 and 1/2 degrees, using his magnifying glass that magnifies everything two times. Under the glass, how large would that angle measure?
Answer: 14 and 1/2 degrees. Explanation, angles remain constant when magnified. A square has 4-90 degree corners, if you zoom in (magnify) a square, it's still a square.
Riddle: King Tut died 120 years after King Eros was born. Their combined age when they died was 100 years. King Eros died in the year 40 B.C. In what year was King Tut born?
Answer: King Tut was born in 20 B.C. There were 120 years between the birth of King Eros and the death of King Tut, but since their ages amounted to only 100 years, there must have been 20 years when neither existed. This would be a period between the death of King Eros, 40 B.C., and the birth of King Tut, 20 B.C.
Riddle: At a children's party, 10 kids had juice, 8 kids had cake, and 6 kids had juice and cake.
How many kids were there at the party?
Answer: Tweleve kids. Six kids had juice and cake, leaving two out of the cake eaters that didn't have juice. As there were ten juicers, there must be twelve kids in total.
Riddle: What is the smallest whole number that is equal to seven times the sum of its digits?
Answer: The answer to this math riddle is 21. You probably just guessed to answer this math riddle, which is fine, but you can also work it out algebraically. The two-digit number ab stands for 10a + b since the first digit represents 10s and the second represents units. If 10a + b = 7(a + b), then 10a + b = 7a + 7b, and so 3a = 6b, or, more simply, a = 2b. That is, the second digit must be twice the first. The smallest such number is 21.
Riddle: Robert and David played several golf matches against each other in a week. They played for a pizza at each match, but no pizzas were purchased until the end of the week. If at any time Robert and David had the same number of wins, those pizzas were canceled. Robert won four matches (but no pizzas), and David won three pizzas. How many rounds of golf were played?
Answer: Eleven, David won 7 matches, 4 to cancel out Robert's 4 wins, and 3 more to win the pizzas.
Riddle: There are two numbers whose product added to the sum of their squares is 109, and the difference of whose squares is 24. What are the two numbers?
Answer: 5 and 7.
(5)² = 25(7)² = 49(5x7)+25+49=10949-25=24
Riddle: Two schoolgirls were traveling from the city to a dacha (summer cottage) on an electric train.
"I notice," one of the girls said "that the dacha trains coming in the opposite direction pass us every 5 minutes. What do you think-how many dacha trains arrive in the city in an hour, given equal speeds in both directions?"
"Twelve, of course," the other girl answered, "because 60 divided by 5 equals 12."
The first girl did not agree. What do you think?
Answer: If the girls had been on a standing train, the first girl's calculations would have been correct, but their train was moving. It took 5 minutes to meet a second train, but then it took the second train 5 more minutes to reach where the girls met the first train. So the time between trains is 10 minutes, not 5, and only 6 trains per hour arrive in the city.
Riddle: Can you combine plus signs and five 2's to get 28? Can you combine plus signs and eight 8's to get 1,000?
Answer: 22+2+2+2=28; 888+88+8+8+8=1,000
