Simple Interest
Math MCQs

Question :    Jennifer took a loan of $4500 at the rate of 6% simple interest per annum. If he paid an amount of $6660 to clear the loan, then find the time period of the loan.

Correct Answer  8

Solution & Explanation

Solution

Given,

Principal (P) = $4500

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

Amount (A) = $6660

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 = $6660 – $4500 = $2160

Thus, Simple Interest = $2160

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 × 2160}/_{4500 × 6}

= ²¹⁶⁰⁰⁰/₂₇₀₀₀

= 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) = $4500

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

Simple Interest = $2160 (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 $4500

= ⁶/₁₀₀ × 4500

= ^{6 × 4500}/₁₀₀

= ²⁷⁰⁰⁰/₁₀₀ = 270

Thus, simple Interest for 1 year = $270

Now,

∵ If the simple Interest is $270, then the time = 1 year

∴ If the simple Interest is $1, then the time = ¹/₂₇₀ years

∴ If the simple Interest is $2160, then the time = ¹/₂₇₀ × 2160 years

= ^{1 × 2160}/₂₇₀ years

= ²¹⁶⁰/₂₇₀ = 8 years

Thus, time (T) = 8 years Answer

Similar Questions

(1) How much loan did Lisa borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7260 to clear it?

(2) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 6% simple interest for 8 years.

(3) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 4% simple interest?

(4) Calculate the amount due if Michael borrowed a sum of $3300 at 8% simple interest for 3 years.

(5) Richard took a loan of $5200 at the rate of 8% simple interest per annum. If he paid an amount of $8944 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Thomas borrowed a sum of $5800 at 5% simple interest for 7 years.

(7) Calculate the amount due if William borrowed a sum of $3500 at 7% simple interest for 3 years.

(8) Calculate the amount due if Barbara borrowed a sum of $3550 at 5% simple interest for 4 years.

(9) Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 7% simple interest.

(10) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 7% simple interest.