Direct Proportion

As one values increases, so does the other.

bal bal

 

 

Unitary method

: Find the value of 1 unit,
Multiply to find the required units.

Example .

4 books cost £ 1.28. How much do 7 books cost ?

1

 

Other methods:

Vedic Method

4:1.28  :: 7: x

2

 

 By the Rule of Three

3

 

This is really just the same as finding a
 scale factor for the cost of the books:-

 

4

 

Indirect Proportion

 

As one values increases, the other decreases.

 

bear

 

 

Example .

If  it takes 4 days for 10 men to dig a trench,
 how long will it take 8 men ?

5

Vedic Method

the first by the first and the last by the last

4:10  :: 8: x

6

 

By the Rule of Three

Since this is indirect proportion,
the inverse applies.

7