Question

Simple interest on an amount at 4% per annum for 13 months is more than the simple
interest on the same sum for 8 months at 6% per annum by Rs. 40. What is the principal
amount?​

Answer 1

Answer:

Rs 12000

Step-by-step explanation:

Interest for 13 months at 4%

Interest per year = 4%

interest per month = 4 ÷ 12 = 1/3 %

Interest for 13 months = 1/3 x 13 = 13/3 %

Interest for 8 months at 6%:

interest per year = 6%

interest per month = 6 ÷ 12 = 0.5%

interest for 8 months = 0.5 x 8 = 4%

 

Define x:

Let the principal amount be x

Solve x:  

13/3% of x - 4% of x = 40  

1/3 % of x = 40

1% of x = 120

100% of x = 120 x 100 = Rs 12000