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 $8160 to clear the loan, then find the time period of the loan.

Correct Answer  10

Solution & Explanation

Solution

Given,

Principal (P) = $5100

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

Amount (A) = $8160

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 = $8160 – $5100 = $3060

Thus, Simple Interest = $3060

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 × 3060}/_{5100 × 6}

= ³⁰⁶⁰⁰⁰/₃₀₆₀₀

= 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) = $5100

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

Simple Interest = $3060 (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 $3060, then the time = ¹/₃₀₆ × 3060 years

= ^{1 × 3060}/₃₀₆ years

= ³⁰⁶⁰/₃₀₆ = 10 years

Thus, time (T) = 10 years Answer

Similar Questions

(1) Lisa took a loan of $6100 at the rate of 6% simple interest per annum. If he paid an amount of $9760 to clear the loan, then find the time period of the loan.

(2) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 2% simple interest?

(3) What amount does John have to pay after 6 years if he takes a loan of $3200 at 7% simple interest?

(4) Calculate the amount due if Christopher borrowed a sum of $4000 at 4% simple interest for 4 years.

(5) William took a loan of $5000 at the rate of 9% simple interest per annum. If he paid an amount of $9500 to clear the loan, then find the time period of the loan.

(6) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 7% simple interest?

(7) Find the amount to be paid if John borrowed a sum of $5200 at 5% simple interest for 8 years.

(8) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 9% simple interest?

(9) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 7% simple interest?

(10) Find the amount to be paid if Joseph borrowed a sum of $5700 at 10% simple interest for 7 years.