Simple Interest
Math MCQs

Question :    Patricia took a loan of $4300 at the rate of 9% simple interest per annum. If he paid an amount of $8170 to clear the loan, then find the time period of the loan.

Correct Answer  10

Solution & Explanation

Solution

Given,

Principal (P) = $4300

Rate of Simple Interest (R) = 9% per annum

Amount (A) = $8170

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 = $8170 – $4300 = $3870

Thus, Simple Interest = $3870

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 × 3870}/_{4300 × 9}

= ³⁸⁷⁰⁰⁰/₃₈₇₀₀

= 10 years (using formula)

Thus, Time (T) = 10 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) = $4300

Rate of Simple Interest (R) = 9% per annum

Simple Interest = $3870 (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 = 9% of Principal

= 9% of $4300

= ⁹/₁₀₀ × 4300

= ^{9 × 4300}/₁₀₀

= ³⁸⁷⁰⁰/₁₀₀ = 387

Thus, simple Interest for 1 year = $387

Now,

∵ If the simple Interest is $387, then the time = 1 year

∴ If the simple Interest is $1, then the time = ¹/₃₈₇ years

∴ If the simple Interest is $3870, then the time = ¹/₃₈₇ × 3870 years

= ^{1 × 3870}/₃₈₇ years

= ³⁸⁷⁰/₃₈₇ = 10 years

Thus, time (T) = 10 years Answer

Similar Questions

(1) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 6% simple interest.

(2) Calculate the amount due if Robert borrowed a sum of $3100 at 2% simple interest for 3 years.

(3) David took a loan of $4800 at the rate of 7% simple interest per annum. If he paid an amount of $6816 to clear the loan, then find the time period of the loan.

(4) Find the amount to be paid if Karen borrowed a sum of $5950 at 6% simple interest for 8 years.

(5) Find the amount to be paid if Jessica borrowed a sum of $5750 at 9% simple interest for 7 years.

(6) In how much time a principal of $3000 will amount to $3120 at a simple interest of 2% per annum?

(7) Calculate the amount due if Richard borrowed a sum of $3600 at 9% simple interest for 4 years.

(8) Calculate the amount due if Linda borrowed a sum of $3350 at 6% simple interest for 4 years.

(9) Calculate the amount due if Patricia borrowed a sum of $3150 at 9% simple interest for 3 years.

(10) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 5% simple interest.