Question

Difference between simple interest and compound interest for one year on the same sum and rate is equal​

Answer 1

Answer:

Given:

Rate of Interest = 20% per annum

Time = 2 years

The difference in Simple Interest and Compound Interest for 2 years = Rs. 625

Formula Used:

The difference between compound interest and simple interest

obtained on Rs. P at R% per annum for 2 years is P(R/100)2

Calculation:

Difference in Simple Interest and Compound Interest for 2 years = P(R/100)2

According to the question,

625 = P × (20/100)2

⇒ 625 = P(1/5)2

⇒ P = 625 × 52

⇒ P = 625 × 5 × 5

⇒ P = 15,625

∴ The sum is Rs. 15,625

Alternate Method

CI = P × [(1 + R/100)n - 1]

⇒ CI = P × [(1 + 20/100)2 - 1]

⇒ CI = P × (36 - 25)/25 = P × (11/25)

SI = PRT/100

⇒ SI = (P × 20 × 2)/100 = P × (2/5)

CI - SI = 11P/25 - 2P/5

⇒ 625 = P/25

⇒ P = 625 × 25 = 15625

∴ The sum is Rs. 15,625

Answer 2

Step-by-step explanation:

In 1st year, C.I is equal to S.I. ∴ Rs. 132 is the difference between the simple interest and compound interest in the 2nd year.