Simple Interest
MCQs Math


Question:     In how much time a principal of $3050 will amount to $3355 at a simple interest of 5% per annum?


Correct Answer  2

Solution And Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (R) = 5% per annum

Amount (A) = $3355

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 = $3355 – $3050 = $305

Thus, Simple Interest = $305

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 × 305/3050 × 5

= 30500/15250

= 2 years (using formula)

Thus, Time (T) = 2 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) = 5% per annum

Simple Interest = $305 (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 = 5% of Principal

= 5% of $3050

= 5/100 × 3050

= 5 × 3050/100

= 15250/100 = 152.5

Thus, simple Interest for 1 year = $152.5

Now,

∵ If the simple Interest is $152.5, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/152.5 years

∴ If the simple Interest is $305, then the time = 1/152.5 × 305 years

= 1 × 305/152.5 years

= 305/152.5 = 2 years

Thus, time (T) = 2 years Answer


Similar Questions

(1) If Jessica borrowed $3750 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(2) Richard had to pay $4140 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

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

(4) Nancy took a loan of $6300 at the rate of 10% simple interest per annum. If he paid an amount of $10080 to clear the loan, then find the time period of the loan.

(5) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 10% simple interest?

(6) Calculate the amount due if Richard borrowed a sum of $3600 at 4% simple interest for 3 years.

(7) Calculate the amount due if Robert borrowed a sum of $3100 at 2% simple interest for 3 years.

(8) Find the amount to be paid if Patricia borrowed a sum of $5150 at 6% simple interest for 7 years.

(9) If Charles borrowed $3900 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(10) Calculate the amount due if Mary borrowed a sum of $3050 at 9% simple interest for 4 years.


NCERT Solution and CBSE Notes for class twelve, eleventh, tenth, ninth, seventh, sixth, fifth, fourth and General Math for competitive Exams. ©