Question

4. In what time would a sum of
money triple itself at 8% p.a.
compound interest? [Given log (1.08)
= 0.03342, log 3 = 0.47712]
O A.,13.28 years​

Answer 1

Answer:

Given that, sum of money become after 8 years it triples Let the sum of money be x

Time is 8 years

After 8 years it triples . So it becomes 3x.

So the simple interest is 3x−x=2x

Let, the rate of interest be y.

So ,

100

x×y×8

=2x

Or,y=

8

200

=25%

Hence, this is the answer.

Answer 2

Given:

In what time would a sum of  money triple itself at 8% p.a.  compound interest?

To Find:

Find the Period.

Solution:

We are given a rate of interest as 8% and says that the money triples itself after a certain period and we need to find the time taken, we can find the solution by using the formula for compound interest that is,

                                     $A=P(1+r)^t$

where,

          A= amount at the end of period

          P= Principal amount

          r= rate of interest

          t= time period

Now let the sum of money be P so the amount at the end of the period will be 3P, so we put it in formula together,

$3P=P(1+0.08)^t\\3=1.08^t$

using the logarithmic function we have,

$Log_{(1.08)}3=t\\t=\frac{Log3}{Log1.08}$

we are given Log1.08=0.03342 and Log3=0.47712

$t=\frac{Log3}{Log1.08} \\=\frac{0.47712}{0.03342} \\=14.27$

Hence, a sum of  money will triple itself at 8% p.a.  compound interest in 14.27 years.