Question

A sum of money becomes 8/5 of itself in 5 years at a certain rate of s.i find the rate of interest

Answer 1

Hello,

Let the principle be rs x
Time is given as 5 years.

So, amount becomes 8x/5

Now ,
We know that
Si = amount - p
SI =8x/5 - x = 3x/5

Now we also know that
$si = \frac{p \times r \times t}{100}$
So as per given values.

$\frac{x \times r \times 5}{100} = \frac{3x}{5} \\ 5x \times r = \frac{3x \times 100}{5} = 60x \\ r = \frac{60x}{5x} = 12\%$


So, the rate of interest is equal to 12 percent per annum.

Hope this will be helping you ✌️

Answer 2

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Refer to the attachment!