Question

A sum of 12000 becomes 17280 at 20% per compound interest. Find the period​

Answer 1

Answer:

ans.

Step-by-step explanation:

amount=17280

p=12000

rate=20%

si=amount -p=5280

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Answer 2

Given: Principal = Rs. 12,000

           Amount = Rs. 17,280

          Compound rate of interest = 20% p.a.

To find: The period in which sum of Rs. 12,000 becomes Rs. 17,280 at 20% p.a. compound interest

Solution: According to the given question,

Principal (P) = Rs. 12,000

Amount = Rs. 17,280

Rate of interest (R) = 20% p.a.

Time (n) = ?

∵ $Amount = Principal(1 + \frac{R}{100}) ^{n}$

⇒ $17,280 = 12,000(1 + \frac{20}{100}) ^{n}$

⇒ $(\frac{120}{100} )^{n} = \frac{17280}{12000} = \frac{36}{25}$

⇒ $(\frac{6}{5}) ^{n} = \frac{6*6}{5*5} = (\frac{6}{5}) ^{2}$

⇒ $n = 2$

Hence, a sum of Rs. 12,000 becomes Rs. 17,280 at 20% p.a. compound interest in 2 years.