A. False – The near-side wheels rotate counter-clockwise, but the far-side wheels rotate clockwise.
B. True
C. False – The acute angle is a little more than 60° because by the time the minute hand reaches 10, the hour hand will have moved slightly past the 4.

Each number is surrounded by a prime number.

4 – 3 and 5 are prime
6 – 5 and 7 are prime
etc.

The next three numbers after 108 that have primes before and after them are:

138, 150 and 180.

742 x 6531 = 4,846,002.

A similar problem can be found in L.A. Graham’s Ingenious Mathematical Problems and Methods with a range of 1 to 9, but the principle remains the same – the numbers with the smallest difference produce the largest product. You start out with the highest two digits, 7 and 6, then attach 5 and 4, putting the smaller of the two digits with the larger number, giving you 74 and 65. The next two highest digits are 3 and 2, giving you 742 and 653. Finally, you add the 1 to the lower number. Page 80 has the details of that solution.

Happenchance. There are two Hs, two As, and so on for all the letters in the word. The longest scientific word with the same property is probably esophagographers.

By setting the snooze time to 9 minutes, the alarm clock only needs to watch the last digit of the time. So, if you hit snooze at 6.45, the alarm goes off again when the last digit equals 4. They couldn’t make it 10 minutes, otherwise the alarm would go off right away, or it would take more circuitry.