Friday Funny: Solution to Cookies, Bananas and Clocks algebra maths puzzle

David Meego - Click for blog homepageIt is time to post the solution to the Cookies, Bananas and Clocks algebra maths puzzle that was posted last month.

If you have not had a go at solving this puzzle and registering your answer on the poll; Stop reading the solution, click on the link above and go do it now.  🙂

The puzzle image is shown below:

Here is the “initial” solution:

  1. There are three cookies which total 30, so each cookie is 10.
  2. There are two bananas and one cookie which total 14, take away 10 so each banana is 2.
  3. There are one banana and two clocks which total 8, take away 2 so each clock is 3.
  4. The final sum is 3 + 2 + 2 x 10.
  5. Doing multiplication first gives 3 + 2 + 20.
  6. So the final answer is 25 …. Which is incorrect.

Look closer at the image and you will notice the following:

  • The cookies have chocolate chips on them, so you are counting chips, not cookies.
  • There are two bananas in each bunch on the second and third lines.
  • The hour hand of the clock has different positions, so you are counting hours not clocks.
  • The final equation has a different hour hand position, single bananas and different number of chips.

So let’s start again with the correct solution:

  1. There are three cookies with 10 chocolate chips each which total 30, so each chip is 1.
  2. There are four bananas and a cookie with 10 chips which total 14, take away 10 so each banana is 1.
  3. There are two bananas and two clocks at 3 o’clock which total 8, table away 2 so each hour is 1.
  4. The clock in the final sum is set to 2 o’clock and the cookie has 7 chocolate chips on it.
  5. The final sum is 2 + 1 + 1 x 7.
  6. Doing multiplication first gives 2 + 1 + 7.
  7. So the final correct answer is 10.

Where you really observant? Did you get it right? At the time of posting the solution, 30% of respondents on the poll were correct, which is not so good. The second most popular response was the initial incorrect answer with 22%.

Keep safe, well and sane.

David

This article was originally posted on http://www.winthropdc.com/blog.

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