Select Page

Each month, a new set of puzzles will be posted.  Come back next month for the solutions and a new set of puzzles, or subscribe to have them sent directly to you.

Challenge 1

A ship is battling against the tide to safety. It uses 7 gallons of fuel every hour and sails at 17 mph in still conditions. It is 77 miles from safety and the flow against it is 6 mph. The ship has 49 gallons of fuel left. Will it reach safety?

Challenge 2

When 4 is added to two numbers, the ratio is 5:6. When 4 is subtracted from the two numbers, the ratio is 1:2. Find the two numbers.

Challenge 3

An unknown airplane flying with a speed of 700 mi/hr is detected 1000 miles away by a radar. Half an hour later an interceptor plane flying with a speed of 800 mi/hr is dispatched. How long will it take the interceptor plane to meet with the unknown plane?

Feedback

There are more than one way of doing these puzzles and may well be more than one answer.  Please let me and others know what alternatives you find by commenting below.  We also welcome general comments on the subject and any feedback you'd like to give.

If you have a question that needs a response from me or you would like to contact me privately, please use the contact form

Get more puzzles!

If you've enjoyed doing the puzzles, consider ordering the books;

• Book One - 150+ of the best puzzles
• Book Two - 200+ with new originals and more of your favourites

Both in a handy pocket sized format.   Click here for full details.

Puzzle 1

In our Community Centre, there is a huge swimming pool with four pipes that can be used to fill the pool.

• The first pipe can fill the pool completely in exactly 2 days.
• The second pipe can fill the pool completely in exactly 3 days.
• The third pipe can fill the pool completely in exactly 4 days.
• The fourth pipe can fill the pool completely in exactly 6 hours.

If all four pipes are used simultaneously, how long will it take to fill up the pool completely?

Solution:

In 1 hour, the ratio of the swimming pool being filled by the four pipes:

1st pipe: 1/48
2nd pipe: 1/72
3rd pipe: 1/96
4th pipe: 1/6

Therefore, 1/48 + 1/72 + 1/96 + 1/6 = 0.0208 + 0.0139 + 0.0104 + 0.1667 = 0.2118
Then, 0.2118 * 24 = 5.083 hrs or approximately 5 hrs (to fill up the pool completely).

Puzzle 2

A farmer wants to plant 19 trees in 9 rows with 5 trees in a row. Show how the farmer can do this?

Solution:

Puzzle 3

Kim threw some darts at this dartboard. Every dart landed on a number on the board and she scored exactly 100. If numbers can be used more than once, how many darts did she throw to score 100 and which numbers did she land on?
(Note: There may be more than one solution.)

Solution:

6 darts (17, 17, 17, 17, 16 and 16)