Simple Interest
Math MCQs

Question :    Barbara took a loan of $5100 at the rate of 6% simple interest per annum. If he paid an amount of $7854 to clear the loan, then find the time period of the loan.

Correct Answer  9

Solution & Explanation

Solution

Given,

Principal (P) = $5100

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

Amount (A) = $7854

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 = $7854 – $5100 = $2754

Thus, Simple Interest = $2754

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 × 2754}/_{5100 × 6}

= ²⁷⁵⁴⁰⁰/₃₀₆₀₀

= 9 years (using formula)

Thus, Time (T) = 9 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) = $5100

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

Simple Interest = $2754 (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 $5100

= ⁶/₁₀₀ × 5100

= ^{6 × 5100}/₁₀₀

= ³⁰⁶⁰⁰/₁₀₀ = 306

Thus, simple Interest for 1 year = $306

Now,

∵ If the simple Interest is $306, then the time = 1 year

∴ If the simple Interest is $1, then the time = ¹/₃₀₆ years

∴ If the simple Interest is $2754, then the time = ¹/₃₀₆ × 2754 years

= ^{1 × 2754}/₃₀₆ years

= ²⁷⁵⁴/₃₀₆ = 9 years

Thus, time (T) = 9 years Answer

Similar Questions

(1) What amount does David have to pay after 5 years if he takes a loan of $3400 at 5% simple interest?

(2) Sandra took a loan of $6900 at the rate of 6% simple interest per annum. If he paid an amount of $10212 to clear the loan, then find the time period of the loan.

(3) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $11084 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Karen borrowed a sum of $3950 at 3% simple interest for 4 years.

(5) Calculate the amount due if John borrowed a sum of $3200 at 10% simple interest for 3 years.

(6) Find the amount to be paid if William borrowed a sum of $5500 at 5% simple interest for 7 years.

(7) Calculate the amount due if Karen borrowed a sum of $3950 at 9% simple interest for 4 years.

(8) Calculate the amount due if Joseph borrowed a sum of $3700 at 7% simple interest for 4 years.

(9) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 2% simple interest.

(10) Jennifer had to pay $3445 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.