Impress your friends with this cool mathematics puzzle. (and know how maths is useful in real life)

This lets you give the age of a person and the number of siblings in their family.

#### Questions that you need to ask

- Think of your age in years
- Multiply your age by 2
- Add 10
- Multiply by 5
- Add number of siblings that you have
- Subtract 50 from this number
- What’s the number?

#### How it Works

If you know an animal called Algebra, this would be a cakewalk for you. How it works is this. Follow the questions….

## Question Answer Example Algebraic Equivalent

2. Multiply your age by 2 30 2[10x+y]

3. Add 10 40 2[10x+y] + 10

4. Multiply by 5 200 5{2[10x+y]+10}=100x+10y+50

5. Add # of siblings you have 203 100x+10y+50+z

6. Subtract 50 153 [100x+10y+50+z]–50= 100x+10y+z

#### Prediction:

#### Explanation:

The algebraic equivalent of the steps result in Step 6, which is 100x + 10y + z, where z<10. But 100x + 10y + z is the algebraic equivalent of a three-digit number, with the digits in the hundreds and tens places giving the age, and the digit in the ones place giving the number of persons in the house. (Note: the number of siblings has to be less than 10, otherwise this “trick” will not work.)