Question

The national wealth of a country increases by $4\%$ of its value at the beginning of every year. Find the national wealth of the country in 1985, if was estimated at INR $3.125\times {10}^{12}$ in 1983.

Answer 1

The National wealth in 1983 was $INR3.125\times {10}^{12}$

The national wealth of a country increases by $4\%$. ie., $4\left(\frac{1}{100}\right)times=\frac{1}{25}times$

The national wealth of the country in 1984 $=(3.125\times {10}^{12}\times \frac{1}{25})+3.125\times {10}^{12}$

$=12.5\times {10}^{10}+3.125\times {10}^{12}$

$=0.125\times {10}^{12}+3.125\times {10}^{12}$

$=3.25\times {10}^{12}$

The national wealth of the country in 1985 $=(3.25\times {10}^{12}\times \frac{1}{25})+3.25\times {10}^{12}$

$=13\times {10}^{10}+3.25\times {10}^{12}$

$=0.13\times {10}^{12}+3.25\times {10}^{12}$

$=3.38\times {10}^{12}$