6 Fast Tricks to Solve Simple Interest

TYPE 1

To calculate Rate of Simple Interest when Principal becomes A/B times of itself:
Trick:1 

Rate of SI =

 

Example 1 

At what rate of simple Interest per annum a sum of money becomes 3/2 times of itself in 5 years?

Solution

Rate of Simple Interest =

TYPE 2

To calculate Rate of Simple Interest when Interest becomes A/B times of Principal:
Trick:2

Example 2 

At what rate of simple Interest a sum of money becomes 4/25 times of Principal. If number of years is equal to the rate of interest?

Solution:

Let time= X (years)

TYPE 3

When a sum of money becomes N1 times in T1 years and N2 times in T2 years

Trick 3   

Example 3

 A sum of money becomes 7 times of itself in 20 years . In how many years it will become 13 times of itself?

Solution:

TYPE 4 

To calculate Time when Principal becomes N times of itself and rate of Simple Interest is given:

Trick 4   

Example 4 

In how many years a sum of money becomes 4 times of itself at 10% rate of simple interest?

Solution        

TYPE 5

To calculate Principal when sum of interest or difference of interest for two different years is given 

Example 5 

At 6 % rate of simple interest per annum the sum of interest for 3 years and 6 years is Rs.270. Calculate the sum?

Solution: