Simple Interest
MCQs Math


Question:     In how much time a principal of $3050 will amount to $3324.5 at a simple interest of 3% per annum?


Correct Answer  3

Solution And Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (R) = 3% per annum

Amount (A) = $3324.5

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 = $3324.5 – $3050 = $274.5

Thus, Simple Interest = $274.5

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 × 274.5/3050 × 3

= 27450/9150

= 3 years (using formula)

Thus, Time (T) = 3 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) = $3050

Rate of Simple Interest (R) = 3% per annum

Simple Interest = $274.5 (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 = 3% of Principal

= 3% of $3050

= 3/100 × 3050

= 3 × 3050/100

= 9150/100 = 91.5

Thus, simple Interest for 1 year = $91.5

Now,

∵ If the simple Interest is $91.5, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/91.5 years

∴ If the simple Interest is $274.5, then the time = 1/91.5 × 274.5 years

= 1 × 274.5/91.5 years

= 274.5/91.5 = 3 years

Thus, time (T) = 3 years Answer


Similar Questions

(1) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 9% simple interest?

(2) If Margaret paid $5046 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(3) If Jennifer borrowed $3250 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(4) Barbara took a loan of $5100 at the rate of 6% simple interest per annum. If he paid an amount of $7548 to clear the loan, then find the time period of the loan.

(5) Find the amount to be paid if Mary borrowed a sum of $5050 at 7% simple interest for 7 years.

(6) Patricia had to pay $3528 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(7) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 2% simple interest?

(8) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 8% simple interest for 3 years.

(9) Find the amount to be paid if John borrowed a sum of $5200 at 10% simple interest for 7 years.

(10) In how much time a principal of $3050 will amount to $3660 at a simple interest of 4% per annum?


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