Thank you to Gareth Matthews, Llantwit Major Comprehensive School for this solution. Jenny Cook, age 15, The Mount School York, Andrei Lazanu, age 12, School 205, Bucharest, Romania and Clement Goh, age 13, from River Valley High School, Singapore all sent good solutions.
I used algebra to get my answer.
| The problem | The solution | My calculation |
|---|---|---|
| First of all, pick the number of times a week that you eat chocolate. | A | 7 |
| Multiply this number by 2 (just to be bold). | 2A (x2) | 14 |
| Add 5 (for Sunday). | 2A+5 (+5) | 19 |
| Multiply it by 50. | 100A+250 (x50) This multiplies the original number by 100 and adds 250 |
950 |
| If you have already had your birthday this year add 1751. If you haven't, add 1750. | 100A+2000 (+1750) Adding 1750 to 250 gives the year I last had a birthday |
2700 |
| Now subtract the four digit year that you were born (if you remember). | 100A + 14 (-1986) Subtracting 1986 from 2000 gives my age. 100A puts the number A in the hundreds place. |
714 |
We can also do it for next year by adding 1752 or 1751.
| A | 7 |
| 2A | 14 |
| 2A+5 | 19 |
| 100A+250 | 950 |
| 100A+2002 (after my birthday) |
2702 (and subtracting 1986) |
| 100A + 16 | 716 |
As you can see it works for next year as well.