- Ask the person to multiply his age by 2.
- Then add 2 to it.
- Multiply the number by 5.
- Ask him to tell you the total.
- Now leave the last number, subtract 1 from it.
- And that's the age.
EXAMPLE:
- Age = 10.
- 10*2=20.
- 20+2=22.
- 22*5=110.
- 110.
- 11-1=10.
His age is 10.
