May 4, 2020

MATH MONDAY - Swipe left if you hate Math Monday

Today’s Puzzle

Find a six-digit number with all unique digits such that, if you take the last digit and move it to the front (i.e. take the rightmost digit and move it all the way to the left), you get a new number that is exactly five times the original.

Friday’s Puzzle - Does your answer hold water?

You have a 5 gallon bucket and a 3 gallon bucket, plus an infinite supply of water. What is the fewest number of steps required to measure exactly 4 gallons? As you might expect, you cannot measure partial buckets.

[SPOILER] Answer to Friday’s Puzzle

Six. The steps are:

1. Fill the 5 gallon bucket.
2. Pour the contents of the 5 gallon bucket into the 3 gallon bucket. (2 gallons remain in the 5 gallon bucket.)
3. Pour out the 3 gallon bucket.
4. Pour the 2 gallons remaining in the 5 gallon bucket into the 3 gallon bucket.
5. Fill the 5 gallon bucket.
6. Pour the contents of the 5 gallon bucket into the 3 gallon bucket (which already has 2 gallons in it). There are now 4 gallons left in the 5 gallon bucket.

Now stop wasting so much water!

The first answer we came up with for this one had eight steps, not six. This was also the first answer that many readers submitted (incidentally, no one who submitted an answer got it right on the first try!):

1. Fill the 3 gallon bucket.
2. Pour the contents of the 3 gallon bucket into the 5 gallon bucket.
3. Fill the 3 gallon bucket.
4. Pour the contents of the 3 gallon bucket into the 5 gallon bucket (1 gallon remains in the 3 gallon bucket).
5. Pour out the 5 gallon bucket.
6. Pour the 1 gallon remaining in the 3 gallon bucket into the 5 gallon bucket.
7. Fill the 3 gallon bucket.
8. Pour the 3 gallon bucket into the 5 gallon bucket. There are now 4 gallons in the 5 gallon bucket.