Question : Richard took a loan of $5200 at the rate of 7% simple interest per annum. If he paid an amount of $8476 to clear the loan, then find the time period of the loan.
Correct Answer 9
Solution & Explanation
Solution
Given,
Principal (P) = $5200
Rate of Simple Interest (R) = 7% per annum
Amount (A) = $8476
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 = $8476 – $5200 = $3276
Thus, Simple Interest = $3276
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 × 3276/5200 × 7
= 327600/36400
= 9 years (using formula)
Thus, Time (T) = 9 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) = $5200
Rate of Simple Interest (R) = 7% per annum
Simple Interest = $3276 (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 = 7% of Principal
= 7% of $5200
= 7/100 × 5200
= 7 × 5200/100
= 36400/100 = 364
Thus, simple Interest for 1 year = $364
Now,
∵ If the simple Interest is $364, then the time = 1 year
∴ If the simple Interest is $1, then the time = 1/364 years
∴ If the simple Interest is $3276, then the time = 1/364 × 3276 years
= 1 × 3276/364 years
= 3276/364 = 9 years
Thus, time (T) = 9 years Answer
Similar Questions
(3) What amount will be due after 2 years if Joseph borrowed a sum of $3350 at a 8% simple interest?
(6) Calculate the amount due if Mary borrowed a sum of $3050 at 2% simple interest for 3 years.
(7) Find the amount to be paid if Thomas borrowed a sum of $5800 at 10% simple interest for 7 years.
(9) Find the amount to be paid if Christopher borrowed a sum of $6000 at 3% simple interest for 7 years.