Question:
Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $9685 to clear the loan, then find the time period of the loan.
Correct Answer
7
Solution And Explanation
Solution
Given,
Principal (P) = $6500
Rate of Simple Interest (R) = 7% per annum
Amount (A) = $9685
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 = $9685 – $6500 = $3185
Thus, Simple Interest = $3185
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 × 3185/6500 × 7
= 318500/45500
= 7 years (using formula)
Thus, Time (T) = 7 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) = $6500
Rate of Simple Interest (R) = 7% per annum
Simple Interest = $3185 (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 $6500
= 7/100 × 6500
= 7 × 6500/100
= 45500/100 = 455
Thus, simple Interest for 1 year = $455
Now,
∵ If the simple Interest is $455, then the time = 1 year
∴ If the simple Interest is $1, then the time = 1/455 years
∴ If the simple Interest is $3185, then the time = 1/455 × 3185 years
= 1 × 3185/455 years
= 3185/455 = 7 years
Thus, time (T) = 7 years Answer
Similar Questions
(1) Calculate the amount due if Thomas borrowed a sum of $3800 at 2% simple interest for 4 years.
(2) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 9% simple interest?
(3) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 4% simple interest?
(4) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $6888 to clear the loan, then find the time period of the loan.
(5) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 4% simple interest?
(6) In how much time a principal of $3050 will amount to $3416 at a simple interest of 3% per annum?
(7) What amount will be due after 2 years if Kenneth borrowed a sum of $4000 at a 10% simple interest?
(8) What amount does Charles have to pay after 5 years if he takes a loan of $3900 at 10% simple interest?
(9) Find the amount to be paid if Barbara borrowed a sum of $5550 at 5% simple interest for 8 years.
(10) Find the amount to be paid if Susan borrowed a sum of $5650 at 10% simple interest for 7 years.