To find Rate when Principal Interest and Time are given

To find Rate when Principal Interest and Time are given the rules are.

Interest = (Principal × Rate × Time)/100

Rate = (100 × Interest)/(Principal × Time)

Examples to find Rate when Principal, Interest and Time are given:

1. Find Rate, when Principal = $ 3000; Interest = $ 400; Time = 3 years.

Solution:

Principal = $ 3000,

Interest = $ 400,

Time = 3 years.

Rate = (100 × Interest)/(Principal × Time)

= (100 × 400)/(3000 × 3)

= 40000/9000

= 4.44 %

Therefore, Rate = 4.44 %.

2. Find Rate, when Principal = $ 2100; Interest = $ 350; Time = 2 years.

Solution:

Principal = $ 2100,

Interest = $ 350,

Time = 2 years.

Rate = (100 × Interest)/(Principal × Time)

= (100 × 350)/(2100 × 2)

= 35000/4200

= 8.33 %

Therefore, Rate = 8.33 %.

3. Find Rate, when Principal = $ 10000; Interest = $ 800; Time = 5 years.

Solution:

Principal = $ 10000,

Interest = $ 800,

Time = 5 years.

Rate = (100 × Interest)/(Principal × Time)

= (100 × 800)/(10000 × 5)

= 80000/50000

= 1.6 %

Therefore, Rate = 1.6 %.

4. Richard deposits 5400 and got back an amount of 6000 after 2 years. Find Richard's interest rate.

Solution:

Amount deposited by Richard = 5400

He received the amount of money after 2 years = 6000

Simple Interest = 6000 – 5400 = 600

Principal = $ 5400

Interest = $ 600,

Time = 2 years.

Rate = (100 × Interest)/(Principal × Time)

= (100 × 600)/(5400 × 2)

= 60000/10800

= 50/9

= 5.555….

= 5.56 %

(Nearest to two decimal place)

Therefore, Rate = 5.56 %.

● Simple Interest.

Word Problems on Simple Interest.

Factors Affecting Interest

In Simple Interest when the Time is given in Months and Days.

To find Principal when Time Interest and Rate are given.

To find Rate when Principal Interest and Time are given .