Question

6. In what time will Rs 1000
amount to Rs 1392.40 at 18%
per annum ,the interest is
compound annually:
O a.4 years
O c.2 years
O d.1 year
O b.3 years​

Answer 1

Step-by-step explanation:

Amount invested = Rs. 1000

Interest rate per annum = 30%

Interest rate per 4 months = 30 ÷ 3 = 10%

Time period will be 12/4 = 3

Amount after one year after compounding every 4 months = P * [1 + R/100]t

⇒ 1000 × [1 + 10 ÷ 100]3

⇒ 1331

Alternate Solution:

Amount invested = Rs. 1000

Interest rate per annum = 30%

Interest rate per 4 months = 30 ÷ 3 = 10%

Time period will be 12/4 = 3

Compound interest = {(3 × 100) + (3 × 10) + 1} = Rs. 331

Amount after one year after compounding in every 4 months

= Principle + Interest = 1000 + 331 = Rs. 1331