Difficulty: Tricky

Gordon is trying to make it big with his Minecraft-themed parody song channel. He spends a lot of time working on each video, and he wants as many views as possible.

Gordon’s noticed some patterns with his view numbers:

  • As soon as he posts a video, he gets 10 views immediately as his subscribers check it out.
  • Over the course of a weekday (Monday, Tuesday, Wednesday, Thursday, Friday), the video will gain 5 views per day.
  • On a weekend day (Saturday, Sunday), the views will double.
  • After 7 days, the algorithm will stop recommending the video and it won’t get any more views.

What day of the week should Gordon post his videos?

Scroll down or click for a hint, or the answer!

brain icon

Brainteaser hint

As there are 7 days in one week, there will be one of each day before the algorithm stops recommending the video.

Weekdays always increase the number of views by 5, but weekend days can add different amounts. How do you make weekend days add bigger numbers of views?

brain icon

Brainteaser answer

The answer is Monday, but how did we get there? One way to approach this puzzle is to imagine a simpler version. What if the week only had one weekday and one weekend day?

If you have the weekend day first, Gordon would get 10 x 2 + 5 = 25 views. If the weekday happens first, Gordon gets (10 + 5) x 2 = 30 views.

Moving back to the question at the top, the weekday views will get doubled on Saturday and Sunday, as long as the weekdays happen before Saturday and Sunday.

To get all 5 weekdays doubled, the video should go out on Monday morning. The total views will be:
(10 + 5 + 5 + 5 + 5 + 5) x 2 x 2 = 140 views.

For more brainteasers and puzzles for kids, subscribe to Double Helix magazine!

Subscribe now! button

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

By submitting this form, you give CSIRO permission to publish your comments on our websites. Please make sure the comments are your own. For more information please see our terms and conditions.

Why choose the Double Helix magazine for your students?

Perfect for ages 8 – 14

Developed by experienced editors

Engaging and motivating

*84% of readers are more interested in science

Engaging students voice