Simple Interest

Questions of Simple Interest

1. Ms. Suchi deposits an amount of Rs. 24,000 to obtain a simple interest at the rate of 14% per annum for 8 years. What total amount will Ms. Suchi get at the end of 8 years?(A) Rs. 62080
   (B) Rs. 28000
   (C) Rs. 50880
   (D) Rs. 26800

   Answer: (C) Rs. 50880

   Solution:
   Formula: Simple Interest (SI) = (P × R × T) / 100
   Principal (P) = Rs. 24,000
   Rate (R) = 14% per annum
   Time (T) = 8 years

   SI = (24000 × 14 × 8) / 100 = 240 × 112 = Rs. 26,880

   Formula: Amount = Principal + Simple Interest
   Amount = 24000 + 26880 = Rs. 50,880

2. A sum of money becomes triple itself in 12 years at simple interest. What is the rate of interest per annum?(A) 12½%
   (B) 16⅔%
   (C) 20%
   (D) 25%

   Answer: (B) 16⅔%

   Solution:
   Let the Principal (P) = x.
   Since the sum becomes triple itself, Amount (A) = 3x.
   Interest (SI) = A − P = 3x − x = 2x.

   Formula: Rate (R) = (SI × 100) / (P × T)
   R = (2x × 100) / (x × 12) = 200 / 12 = 50 / 3 = 16⅔%

3. At what rate per annum simple interest will a principal of Rs. 5,000 amount to Rs. 6,200 in 3 years?(A) 6%
   (B) 8%
   (C) 10%
   (D) 12%

   Solution:
   Principal (P) = Rs. 5,000
   Amount (A) = Rs. 6,200
   Time (T) = 3 years
   Interest (SI) = 6200 − 5000 = Rs. 1,200

   Rate (R) = (1200 × 100) / (5000 × 3) = 8%

4. A sum of Rs. 1,600 gives a simple interest of Rs. 252 in 2 years and 3 months. Find the rate of interest per annum.(A) 6%
   (B) 7%
   (C) 8%
   (D) 9%

   Answer: (B) 7%

   Solution:
   Time (T) = 2 years 3 months = 2 + (3 / 12) = 2.25 years = 9 / 4 years.

   Rate (R) = (SI × 100) / (P × T)
   R = (252 × 100) / (1600 × (9 / 4)) = (252 × 100 × 4) / (1600 × 9) = 7%

5. In how many years will a sum of Rs. 3,000 yield a simple interest of Rs. 1,080 at 12% per annum?(A) 2 years
   (B) 3 years
   (C) 4 years
   (D) 5 years

   Answer: (B) 3 years

   Solution:
   Time (T) = (SI × 100) / (P × R)
   T = (1080 × 100) / (3000 × 12) = 3 years