Simple Interest
MCQs Math


Question:     Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $9360 to clear the loan, then find the time period of the loan.


Correct Answer  8

Solution And Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (R) = 7% per annum

Amount (A) = $9360

Thus, time (T) = ?

Method (1) Using Formula

Calculation of Simple Interest, when Principal and Amount are given

Formual to Calculate Simple Interest when Principal and Amount are given

We know that, Amount (A) = Principal (P) + Simple Interest (SI)

⇒ Simple Interest (SI) = Amount – Principal

⇒ SI = $9360 – $6000 = $3360

Thus, Simple Interest = $3360

Calculation of the Time using forumula when Amount, Simple Interest and Principal are known

Formula to find the Time (T)

Time (T) = 100 × Simple Interest/Principal × Rate of Interest

⇒ T = 100 × SI/P × R

Thus, Time (T) = 100 × 3360/6000 × 7

= 336000/42000

= 8 years (using formula)

Thus, Time (T) = 8 years (from time taken before calculation)Answer

Calculation of the Time using Unitary Method when Amount, Simple Interest and Principal are known

Here, we have

Principal (P) = $6000

Rate of Simple Interest (R) = 7% per annum

Simple Interest = $3360 (As calculated above by subtracting Principal from the Amount given)

We know that, interest is calculated on the basis of the Principal.

This means Simple Interest for 1 year = Rate of simple interest × Principal

Thus, Simple Interest for 1 year = 7% of Principal

= 7% of $6000

= 7/100 × 6000

= 7 × 6000/100

= 42000/100 = 420

Thus, simple Interest for 1 year = $420

Now,

∵ If the simple Interest is $420, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/420 years

∴ If the simple Interest is $3360, then the time = 1/420 × 3360 years

= 1 × 3360/420 years

= 3360/420 = 8 years

Thus, time (T) = 8 years Answer


Similar Questions

(1) Find the amount to be paid if Karen borrowed a sum of $5950 at 10% simple interest for 8 years.

(2) Find the amount to be paid if Michael borrowed a sum of $5300 at 4% simple interest for 8 years.

(3) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 7% simple interest?

(4) Karen took a loan of $5900 at the rate of 8% simple interest per annum. If he paid an amount of $10148 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if John borrowed a sum of $3200 at 10% simple interest for 4 years.

(6) Patricia took a loan of $4300 at the rate of 9% simple interest per annum. If he paid an amount of $7783 to clear the loan, then find the time period of the loan.

(7) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 10% simple interest?

(8) Calculate the amount due if John borrowed a sum of $3200 at 7% simple interest for 3 years.

(9) Calculate the amount due after 10 years if David borrowed a sum of $5400 at a rate of 6% simple interest.

(10) William had to pay $3920 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.


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