AGE BY CHOCOLATE!

There's been an email trick going round that works like this:

First of all, pick the number of times a week that you would like to have chocolate (more than once but less than 10) Let's assume it's 7

Multiply this number by 2 7 x 2 = 14.

Add 5 14 + 5 = 19

Multiply it by 50.
You might need the chocolate calculator!
19 x 50 = 950

If you have already had your birthday this year add 1775*. If you haven't, add 1774*
* These numbers make the trick work in the year 2025.
In 2026, use 1776 if you've had your birthday or 1775 if not.
In 2027, use 1777 if you've had your birthday or 1776 if not.
Let's say it's the year 2025 and we've had a birthday so we add 1775 +950 to get 2725.

Now subtract the four digit year that you were born. Let's say we were born in 1998, so 2725 - 1998 = 727

You should end up with a three digit number.
The first digit is the number of times you like chocolate in the week.
The last two digits are your age!
Yes!
7 is the number picked and if we were born in 1998, then in 2025 (after our birthday) we would be 27 years old!

So what's going on?

This is a variation on the old "Think of a Number" trick which can be explained with algebra.

First of all, when we look at the answer 725, we know the 7 is the number we chose for chocolate. The trick makes sure that this number is multiplied by 100 so that it appears in the "hundreds" place in the answer.

As for the age, all the trick does is subtract your year of birth from this year, but it does it in a disguised way. Instead of just subtracting from 2020, it first adds 250 + 1770 to get 2020 before you subtract your birth year.

Confused? Never mind, let's do it again with algebra...

Pick the number of times a week that you would like to have chocolate. Let's call it C

Multiply this number by 2 2 x C = 2C.

Add 5 2C + 5

Multiply it by 50 ! You have to make sure you multiply both bits by 50 !
You get 50(2C+5) = 50 x 2C + 50 x 5 = 100C + 250

If you have already had your birthday this year add 1775*.
If you haven't, add 1774*. If we've had a birthday we get
100C + 250 + 1775 = 100C + 2025
If we haven't had a birthday we get
100C + 250 + 1774 = 100C + 2024.
This would make the age in the final answer one year less.

Now subtract the four digit year that you were born. If we were born in 1998 then:
100C + 2025 - 1998 = 100C + 27

You should end up with a three digit number.
The first digit is the number of times you like chocolate in the week.
The last two digits are your age!
As you can see, the three digit number is made up of 100C,
(which puts your chocolate digit at the front)
and the last two digits are your age.

How many snaps does it take to break up a chocolate bar?
You might find this puzzle tastier than the algebra!

It takes 5 snaps to break up this little bar into the six squares. (You're not allowed to break two pieces at the same time.)
These bars both have 12 squares. Which will need the most snaps? Or will they both need the same number?
You can find the answer on this page:
Easy Questions Evil Answers

You'll find a lot more great tricks and how they all work in
The Phantom X

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Links:
Tricks and Games
The Murderous Maths Home Page