Question

A certain sum of money amounts to rupees 2900 at 4% per annum in 4 years. In how many years will it amount to rupees 5000 at the same rate?

Answer 1

$2900=P+P(\frac{4}{100}{)}^4$

$\Rightarrow 2900=P(1+\frac{16}{100})$

$\Rightarrow 2900=P\left(\frac{116}{100}\right)\Rightarrow P=\frac{2900\times 100}{116}=Rs2500$

$5000=2500+2500\left(\frac{4}{100}\right)t$

$\Rightarrow 5000-2500=\frac{2500\times 4t}{100}$

$\Rightarrow 2500=2500\times \frac{4t}{100}\Rightarrow 4t=100$

$\Rightarrow t=25$ years