Noah and Emma, track stars with superb hearing, ran as fast as they could to catch up to the ice cream truck in the next town over. They averaged 6 miles per hour, then rested to enjoy their ice cream. They averaged 4 miles per hour over the same distance on the way back. Not counting the time they rested, what was their average speed?
4.8 miles per hour. 5 mph is tempting, but incorrect. Pick any distance, say 12 miles there and 12 miles back. They take two hours to cover the first 12 miles and three hours to cover the return trip. In 5 hours they covered 24 miles which is an overall average of 4.8 miles per hour.
The moon. It has two sides, but on earth we only ever see one side. Man has been on the moon, but no one is there now. A full lunar eclipse is known as a blood moon, and the phrase “once in a blue moon” refers to something that rarely happens. Promising the moon is making an extravagant or impossible promise, and there’s a new moon once every lunar cycle.
7. The digits represent the number of letters in each word of the puzzle. “What” has four letters, “digit” has five letters, “should” has six letters, etc. The last word is “numbers” which has seven letters.
Four cards are placed in front of you on the table, each with a number on one side and a color on the other. The visible cards show 3, 8, red and brown. Which cards should you turn over in order to test the truth of the statement that if a card shows an even number on one face, then its opposite face is red?
You’d need to turn over only the 8 and brown card. Only a card with an even number on one face and which is not red on the other face can invalidate the stated rule. If you turn over the 3 card and it’s not red, it doesn’t invalidate the rule, nor does turning over the red card and finding it has the label 3.
This test was devised by Peter Cathcart Wason and is known as the Wason selection task. Less than 10% of test subjects got it correct in two separate studies.
