391. What is the next number in this series?
21, 20, 18, 15, 11, ________?
392. What is represented by the wacky word?
393. Can you complete this grid of letters. Each line is a valid 5 letter word
with its first and last letter missing. The missing letters form a word when read downwards and the same word appears both at the start and at the end. What
is the missing word?
394. There are two bars of iron. One bar is magnetized along its length, while the
other is not magnetized. Using just the two bars, without any other items, how can you tell which bar is magnetized and which is not?
395. If a crab and a half weigh a pound and a half, but the half crab weighs half
as much again as the whole crab, what do half the whole crab and the whole of the half crab weigh?
396. A man was telling me on a particular occasion, "The day before yesterday
I was 35 years old and next year I will turn 38." How can this be?
397. Using the numbers 1, 9, 9 and 9, in that order,
make the number 89. You may use brackets and any standard math operation such as the square root, +, -, * and /. For example, 26 = -1 + 9 + 9 + 9.
398. When you say my name, I no longer exist. What am I?
399. What is the number which is 4 times the number that is one-eighth of
one-tenth of one-half of 640
400. What is represented by this wacky word?
401. Which is larger, the number of seconds in a day or the number hours in 10
402. What number is two-thirds of one-half of one-fourth of 240?
403. A recycling factory makes its own paper cups for
canteen use. It can make one new cup from nine used ones. If it has 515 used cups how many can it possibly make in total?
404. A truck became wedged under a low bridge. It could not move forward or
back without severely damaging its roof. The truck driver was perplexed until a little girl standing nearby suggested an easy solution. What was it?
405. Two clocks were correct at midnight but then one began
to gain four minutes every hour. It stopped one and a half hours ago showing 4:48 pm. The clocks run for less than 24 hours. What time will the other clock be showing?