This is a Handy Rule of Three that will help you out to solve those little math problems you may encounter in your daily life.

Handy Rule of Three supports the direct and inverse rule of three.

Direct mode C*B/A
If an exam has 30 questions which makes 100%
What percentage makes 24 correct answers?

x= 20*100/30
x= 80

Inverse mode A*B/C:
If making dinner takes 3 hours to 2 people.
How long would it take to 1 person?

x= 3*2/1
x= 6