Question

1. A sum of money amounts to Rs.15360 in 4 years. If the rate of interest is increased by 20% the amount becomes Rs.16032 in same time. Then find the rate of interest?

Answer 1

The rate of interest in 7%pa.

• A sum of money amounts to Rs.15360 in 4 years.

• Let the principal amount be P and the rate of interest be R.

• Now , the formula to obtain the sum of money is

Amount = P + $\frac{PNR}{100}$

• Now, substituting the given values we get

15360 = P($1 + \frac{4R}{100}$)    (Equation 1)

• Now , If the rate of interest is increased by 20% the amount becomes Rs.16032 in same time.

Rate of interest becomes 1.2R.

16032 = P($1 + \frac{4(1.2R)}{100}$)

16032 = P($1 + \frac{4.8R}{100}$)    (Equation 2)

• Dividing equation 1 by 2, we get

$\frac{15360}{16032}$ = $\frac{1 + \frac{4R}{100}}{1 + \frac{4.8R}{100}}$

1536000 + 73728R = 1603200 + 64128R

9600R = 67200

R = 67200/9600

R = 7

• The rate on interest is 7 pcpa(percent per annum).

Answer 2

Answer:

The answer is 7%

Step-by-step explanation:

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