Question

If simple interest on a
certain
sum of money for 4yr at 5% p.a. is same for as the simple interest
$840 for 10 yr at the
rate of 4% p.m., the sum of the

money is :​

Answer 1

For first case,

P = ?

T = 4 years

R = 5% p.a.

We know

$si = \frac{ptr}{100}$

$= \frac{p \times 4 \times 5}{100}$

$= \frac{20p}{100}$

$= \frac{p}{5}$

Now, for second case,

P = $840

T = 10 years

R = 4% p.a.

$si = \frac{ptr}{100}$

$= \frac{840 \times 10 \times 4}{100}$

$= 84 \times 4$

$= 336$

According to question,

$\frac{p}{5} = 336$

$p = 336 \times 5$

$p = 1680$

Therefore, the sum of money was $1680.