Question

A sum of money becomes $\frac{8}{5}$ of itself in $5$ days at certain $5$ rate of simple interest. Find the rate of interest ?

Answer 1

$A=\frac{8}{5}P$

$A=P+SI$

$⟹A=P+\left(\frac{P\times r\times t}{100}\right)$

$⟹\frac{8}{5}P=P[1+(\frac{r\times 5}{100}\left)\right]$

$⟹r=12\%$