Question

plz plz solve this problem..............

Answer 1

Solution ●●●●
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19)
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Given,

Principal ( P ) = ₹ 640

Amount ( A ) = ₹ 774.40

Time ( T ) = 2 years

Let the rate be R% p.a.

Now, We know that

$Amount = P \times (1 + \frac{R}{100} ) {}^{T} \\ \\ = > 774.40 = 640 \times (1 + \frac{R}{100} ) {}^{2} \\ \\ = > \frac{77440}{100 \times 640} = (1 + \frac{R}{100} ) {}^{2} \\ \\ = > \frac{121}{100} = (1 + \frac{R}{100} ) {}^{2}$

$= > ( \frac{11}{10} ) {}^{2} = (1 + \frac{R}{100} ) {}^{2} \\ \\ = > \frac{11}{10} = 1 + \frac{R}{100} \\ \\ = > \frac{11}{10} - 1 = \frac{R}{100} \\ \\ = > \frac{11 - 10}{10} = \frac{R}{100} \\ \\ = > \frac{1}{10} = \frac{R}{100}$

$= > 10R = 100 \\ \\ = > R = \frac{100}{10} \\ \\ = > R = 10$

Hence, the rate is 10% p.a.
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I hope it will help you