Question:
In how much time a principal of $3200 will amount to $3520 at a simple interest of 2% per annum?
Correct Answer
5
Solution And Explanation
Solution
Given,
Principal (P) = $3200
Rate of Simple Interest (R) = 2% per annum
Amount (A) = $3520
Thus, time (T) = ?
Method (1) Using Formula
Calculation of Simple Interest, when Principal and Amount are givenFormual 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 = $3520 – $3200 = $320
Thus, Simple Interest = $320
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 × 320/3200 × 2
= 32000/6400
= 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) = $3200
Rate of Simple Interest (R) = 2% per annum
Simple Interest = $320 (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 = 2% of Principal
= 2% of $3200
= 2/100 × 3200
= 2 × 3200/100
= 6400/100 = 64
Thus, simple Interest for 1 year = $64
Now,
∵ If the simple Interest is $64, then the time = 1 year
∴ If the simple Interest is $1, then the time = 1/64 years
∴ If the simple Interest is $320, then the time = 1/64 × 320 years
= 1 × 320/64 years
= 320/64 = 5 years
Thus, time (T) = 5 years Answer
Similar Questions
(1) Find the amount to be paid if David borrowed a sum of $5400 at 10% simple interest for 8 years.
(2) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 8% simple interest.
(3) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 8% simple interest.
(4) Calculate the amount due if John borrowed a sum of $3200 at 2% simple interest for 3 years.
(5) Calculate the amount due if Jessica borrowed a sum of $3750 at 5% simple interest for 4 years.
(6) Calculate the amount due if Jennifer borrowed a sum of $3250 at 6% simple interest for 3 years.
(7) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 10% simple interest?
(8) Calculate the amount due if Michael borrowed a sum of $3300 at 3% simple interest for 3 years.
(9) If Susan paid $3942 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(10) Find the amount to be paid if Robert borrowed a sum of $5100 at 3% simple interest for 7 years.