Simple Interest
MCQs Math


Question:     Elizabeth took a loan of $4900 at the rate of 6% simple interest per annum. If he paid an amount of $6664 to clear the loan, then find the time period of the loan.


Correct Answer  6

Solution And Explanation

Solution

Given,

Principal (P) = $4900

Rate of Simple Interest (R) = 6% per annum

Amount (A) = $6664

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 = $6664 – $4900 = $1764

Thus, Simple Interest = $1764

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 × 1764/4900 × 6

= 176400/29400

= 6 years (using formula)

Thus, Time (T) = 6 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) = $4900

Rate of Simple Interest (R) = 6% per annum

Simple Interest = $1764 (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 = 6% of Principal

= 6% of $4900

= 6/100 × 4900

= 6 × 4900/100

= 29400/100 = 294

Thus, simple Interest for 1 year = $294

Now,

∵ If the simple Interest is $294, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/294 years

∴ If the simple Interest is $1764, then the time = 1/294 × 1764 years

= 1 × 1764/294 years

= 1764/294 = 6 years

Thus, time (T) = 6 years Answer


Similar Questions

(1) Calculate the amount due if Joseph borrowed a sum of $3700 at 5% simple interest for 4 years.

(2) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 2% simple interest?

(3) In how much time a principal of $3150 will amount to $3622.5 at a simple interest of 5% per annum?

(4) What amount will be due after 2 years if Anthony borrowed a sum of $3650 at a 8% simple interest?

(5) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 7% simple interest for 8 years.

(6) Find the amount to be paid if Robert borrowed a sum of $5100 at 10% simple interest for 8 years.

(7) What amount does Karen have to pay after 6 years if he takes a loan of $3950 at 8% simple interest?

(8) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 6% simple interest?

(9) Find the amount to be paid if James borrowed a sum of $5000 at 7% simple interest for 8 years.

(10) Find the amount to be paid if Charles borrowed a sum of $5900 at 9% simple interest for 7 years.


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