Simple Interest
MCQs Math


Question:     Lisa took a loan of $6100 at the rate of 8% simple interest per annum. If he paid an amount of $9516 to clear the loan, then find the time period of the loan.


Correct Answer  7

Solution And Explanation

Solution

Given,

Principal (P) = $6100

Rate of Simple Interest (R) = 8% per annum

Amount (A) = $9516

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 = $9516 – $6100 = $3416

Thus, Simple Interest = $3416

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 × 3416/6100 × 8

= 341600/48800

= 7 years (using formula)

Thus, Time (T) = 7 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) = $6100

Rate of Simple Interest (R) = 8% per annum

Simple Interest = $3416 (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 = 8% of Principal

= 8% of $6100

= 8/100 × 6100

= 8 × 6100/100

= 48800/100 = 488

Thus, simple Interest for 1 year = $488

Now,

∵ If the simple Interest is $488, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/488 years

∴ If the simple Interest is $3416, then the time = 1/488 × 3416 years

= 1 × 3416/488 years

= 3416/488 = 7 years

Thus, time (T) = 7 years Answer


Similar Questions

(1) How much loan did Ronald borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $9000 to clear it?

(2) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 5% simple interest?

(3) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 10% simple interest for 7 years.

(4) Calculate the amount due if Michael borrowed a sum of $3300 at 10% simple interest for 3 years.

(5) Find the amount to be paid if David borrowed a sum of $5400 at 10% simple interest for 8 years.

(6) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 9% simple interest.

(7) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 2% simple interest.

(8) Calculate the amount due if James borrowed a sum of $3000 at 3% simple interest for 3 years.

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

(10) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 7% simple interest.


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