Simple Interest
MCQs Math


Question:     Mary took a loan of $4100 at the rate of 8% simple interest per annum. If he paid an amount of $6724 to clear the loan, then find the time period of the loan.


Correct Answer  8

Solution And Explanation

Solution

Given,

Principal (P) = $4100

Rate of Simple Interest (R) = 8% per annum

Amount (A) = $6724

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 = $6724 – $4100 = $2624

Thus, Simple Interest = $2624

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 × 2624/4100 × 8

= 262400/32800

= 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) = $4100

Rate of Simple Interest (R) = 8% per annum

Simple Interest = $2624 (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 = 8% of Principal

= 8% of $4100

= 8/100 × 4100

= 8 × 4100/100

= 32800/100 = 328

Thus, simple Interest for 1 year = $328

Now,

∵ If the simple Interest is $328, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/328 years

∴ If the simple Interest is $2624, then the time = 1/328 × 2624 years

= 1 × 2624/328 years

= 2624/328 = 8 years

Thus, time (T) = 8 years Answer


Similar Questions

(1) Sarah had to pay $4427.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(2) What amount does Joseph have to pay after 5 years if he takes a loan of $3700 at 8% simple interest?

(3) Find the amount to be paid if David borrowed a sum of $5400 at 4% simple interest for 8 years.

(4) In how much time a principal of $3150 will amount to $3780 at a simple interest of 4% per annum?

(5) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 8% simple interest?

(6) What amount does James have to pay after 6 years if he takes a loan of $3000 at 10% simple interest?

(7) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 5% simple interest?

(8) Sarah took a loan of $5700 at the rate of 6% simple interest per annum. If he paid an amount of $8436 to clear the loan, then find the time period of the loan.

(9) If Steven paid $5520 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(10) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 5% simple interest.


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