Simple Interest
Math MCQs

Question :    Richard took a loan of $5200 at the rate of 6% simple interest per annum. If he paid an amount of $8320 to clear the loan, then find the time period of the loan.

Correct Answer  10

Solution & Explanation

Solution

Given,

Principal (P) = $5200

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

Amount (A) = $8320

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 = $8320 – $5200 = $3120

Thus, Simple Interest = $3120

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 × 3120}/_{5200 × 6}

= ³¹²⁰⁰⁰/₃₁₂₀₀

= 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) = $5200

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

Simple Interest = $3120 (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 $5200

= ⁶/₁₀₀ × 5200

= ^{6 × 5200}/₁₀₀

= ³¹²⁰⁰/₁₀₀ = 312

Thus, simple Interest for 1 year = $312

Now,

∵ If the simple Interest is $312, then the time = 1 year

∴ If the simple Interest is $1, then the time = ¹/₃₁₂ years

∴ If the simple Interest is $3120, then the time = ¹/₃₁₂ × 3120 years

= ^{1 × 3120}/₃₁₂ years

= ³¹²⁰/₃₁₂ = 10 years

Thus, time (T) = 10 years Answer

Similar Questions

(1) Find the amount to be paid if Barbara borrowed a sum of $5550 at 9% simple interest for 7 years.

(2) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 3% simple interest?

(3) Calculate the amount due if Mary borrowed a sum of $3050 at 5% simple interest for 4 years.

(4) Calculate the amount due if Jessica borrowed a sum of $3750 at 8% simple interest for 3 years.

(5) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 3% simple interest.

(6) How much loan did Thomas borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6380 to clear it?

(7) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 7% simple interest?

(8) Calculate the amount due if Joseph borrowed a sum of $3700 at 10% simple interest for 4 years.

(9) Find the amount to be paid if Robert borrowed a sum of $5100 at 7% simple interest for 8 years.

(10) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 10% simple interest.