Question

an amount becomes 6 times in 7 years when invested under s.i. at a certain rate in how many years will the amount become 16 times of the original amount at the same rate

Answer 1

In 18 year 6 month the amount will

Answer 2

Solution:

In 21 years the original amount becomes 16 times.

Explanation:

The formula for simple interest is

$SI=P\cdot r \cdot t$, where r is in decimal.

Let the original amount be x.

Now, we have been given that the amount becomes 6 times in 7 years. Thus, we have

$6x-x=x\cdot r \cdot 7\\\\5x=x\cdot r \cdot 7\\\\r=\frac{5}{7}$

Now, we have to find the time when the original amount becomes 16 times.

Thus, we have

$16x-x=x\cdot\frac{5}{7}\cdot t\\\\ 15x=x\cdot\frac{5}{7}\cdot t\\\\t=21$

Therefore, in 21 years the original amount becomes 16 times.