Simple Interest
MCQs Math


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


Correct Answer  5

Solution And Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (R) = 4% per annum

Amount (A) = $3660

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 = $3660 – $3050 = $610

Thus, Simple Interest = $610

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 × 610/3050 × 4

= 61000/12200

= 5 years (using formula)

Thus, Time (T) = 5 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) = 4% per annum

Simple Interest = $610 (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 = 4% of Principal

= 4% of $3050

= 4/100 × 3050

= 4 × 3050/100

= 12200/100 = 122

Thus, simple Interest for 1 year = $122

Now,

∵ If the simple Interest is $122, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/122 years

∴ If the simple Interest is $610, then the time = 1/122 × 610 years

= 1 × 610/122 years

= 610/122 = 5 years

Thus, time (T) = 5 years Answer


Similar Questions

(1) Susan took a loan of $5300 at the rate of 7% simple interest per annum. If he paid an amount of $7897 to clear the loan, then find the time period of the loan.

(2) If Robert borrowed $3100 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(3) Find the amount to be paid if James borrowed a sum of $5000 at 9% simple interest for 7 years.

(4) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 6% simple interest?

(5) Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 9% simple interest.

(6) Find the amount to be paid if Linda borrowed a sum of $5350 at 5% simple interest for 8 years.

(7) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 2% simple interest?

(8) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 10% simple interest?

(9) Find the amount to be paid if John borrowed a sum of $5200 at 4% simple interest for 8 years.

(10) Richard took a loan of $5200 at the rate of 10% simple interest per annum. If he paid an amount of $8840 to clear the loan, then find the time period of the loan.


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