In this Worksheet on Simple Interest, we can see the questions on calculating simple interest, rate of interest, and the amount, which is useful to the students so that they can practice for their examinations or any competitive tests. Given below are different types of questions with solutions that help you to understand the chapter better. Assess your preparation level by solving the Simple Interest Worksheet Questions on your own.
Here to solve the questions on simple interest we will use the formula,
Simple interest (S.I.) = (Principal × Rate× Time)/100 and to calculate the Amount
Amount (A) = Principal +Interest
1. Find the simple interest and amount in each of the following:
(a) P = $30,000 R = 10% T = 5 years
Solution:
Given:
Principal= $30,000
Rate= 10%
Time= 5 years.
To find Simple interest we will use the formula,
Simple interest (S.I.) = (Principal × Rate× Time)/100
= (30,000×10×5)/100
By solving we will get
Simple interest = $15,000.
(b) P= $17000 R= 20% T= 30 days
Solution:
Given:
Principal= $17,000
Rate= 20%
Time= 30 days
Here we will convert days to years by dividing with 365 i.e 30/365, then substitute the given values in the formula,
= (17000×20×30)/100×365
by solving we will get
Simple interest = $279.45
(c) P= $6000 R= 15% T= 13 months
Solution:
Given:
Principal= $6000
Rate= 15%
Time= 13 months
Here we have to convert months to years, so we will divide with 12
13÷12= 1.08 years
Simple interest (S.I.) = (Principal × Rate× Time)/100
= $975.
(d) P= $500 R= 3% T= 1 1/2 year
Solution:
Given:
Principal= $500
Rate= 3%
Time= 1 1/2 year= 1.5 years.
Simple interest (S.I.) = (Principal × Rate× Time)/100
= $1,350.
2. What sum would yield an interest of $80 in 4 years at 4% p.a.?
Solution:
Given:
Interest= $80
Time= 4 years
Rate= 4%
Principal = Interest×100/ Rate×Time
= 80×100/ 4×4
= $500.
3. At what rate percent per annum will $550 amount to $650 in 4 years?
Solution:
Given:
Amount= $650
Principal= $550
Time = 4 years
Simple interest= Amount – Principal
= $650 – $550
=$100
So Rate= Simple interest ×100 / Principal×Time
= 100×100 / 550× 4
= 4.5%
4. In what time will $800 amount to $1050 if the simple interest is calculated at 15% p.a.?
Solution:
Given:
Amount= $1050
Principal= $800
Rate = 15%
Simple interest= Amount – Principal
= $1050-$800
= $250
Time= Simple interest ×100 / Principal×Rate
= 250×100 / 800×15
= 2 1/12 years.
5. A sum amount to $1500 at 5% simple interest per annum after 3 years. Find the sum.
Solution:
Given:
Amount payable = $1500
Rate= 5%
Time= 3 years
So amount payable= Principal(100+r×t)/100
1500= Principal(100+5×3)/100
By solving we will get
Principal= $1304.34
6. Mr.Mike borrowed $5500 from Sam at 5% per annum. After 5 years he cleared the amount by giving $8,500 cash and a bag. Find the cost of the bag.
Solution:
Given:
Principal= $5,500
Rate= 5%
Time= 5 years
Simple interest (S.I.) = (Principal × Rate× Time)/100
= $1,375.
The total amount to be cleared after 5 years= Principal+Interest
= $1,375+$5,500
= $6,875
Mike cleared by paying $8,500 and a bag,
So the cost of the bag is
= $8,500-$6,875
= $1,625
8. In how many years will $7000 yield an interest of $4620 at 22% simple interest?
Solution:
Given:
Principal= $7,000
Simple interest= $4,620
Rate= 22%
Time=
$4,620= (7,000×22×Time)/100
By solving
Time= 3.04 years
9. At what rate of simple interest will $2800 amount to $3500 in 2 years, 3 months?
Solution:
Given:
Principal= $2,800
Amount= $3,500
Time= 2 years 3 months = 9/4 years
Simple interest= amount – principal
= $3,500 – $2,800
= $700
Rate= (Simple interest × 100)/ Principal× time
By substituting the values we will get rate= 11.1%
10. Find the simple interest at the rate of 8% p.a. for 4 years on that principal which in 6 years, 6 months at the rate of 4% p.a. gives $1600 as simple interest.
Solution:
Given:
Rate= 4%
Time= 6 years 6 months which is 13/2 years
Simple interest= $1600
As Principal = (Simple interest × 100)/ Rate× time
= 1600×100×2 / 13×4
= $6153.84
Now Simple interest for 4 years is
= (6153.84×4×8)/100
= $1969.22
11. Simple interest on a certain sum is 36/72 of the sum. Find the rate percent and time if both are numerically equal. [Hint: (T = R), P = x, S.I. = 36/72x]
Solution:
Let Sum be X
Time= Rate= R
Simple interest= 36/72X
Simple interest (S.I.) = (Principal × Rate× Time)/100
36/72X =(X × R × R)/100
on solving we will get 7% approx.
12. Simple interest on a sum of money at the end of 5 years is 2/5 of the sum itself. Find the rate percent p.a.
Solution:
Let Principal be X
Time= 5 years
Simple interest= 2/5X
Simple interest (S.I.) = (Principal × Rate× Time)/100
2/5X= ( X × R × 5)/100
on solving we will get
Rate= 8%