correct answer is: c) Rs 10500

Explanation

Here,
Rate (r) = 8\% p.a.
Time (t) = 6 months or \large\frac{6}{12} years \large\frac{1}{2} years
Amount due = Rs 10920
Let, Principal = ‘p’
We need to find the present worth of the sum (p) .
We know, S.I. = (Amount – Principal)
\therefore S.I. = Rs \left(10920-p\right)

Now,
S.I. =\large\frac{p\ \times\ t\ \times\ r}{100}
\rightarrow\left(10920-p\right)=\large\frac{p\times1\times8}{100\times2}
\rightarrow\left(10920-p\right)=\large\frac{8p}{200}
\rightarrow(10920-p)=\large\frac{p}{25}
\rightarrow25\left(10920-p\right)=p _{[cross multiply]}
\rightarrow27300-25p=p
\rightarrow\left(-25p-p\right)=-27300
\rightarrow26p=27300
\rightarrow p=\large\frac{27300}{26}
\rightarrow p=10500
\therefore The present worth of the sum (p) = Rs 10500
Ans: The present worth of a sum of Rs 10920 due six months hence at 8% per annum simple interest is Rs 10500.

There’s another way to pose this same question:
1. What is the method for determining the present value of Rs 10920 with a maturity period of six months and an 8% p.a. simple interest rate?
2. What formula can I use to find the present worth of Rs 10920 due in six months at 8% p.a. simple interest?
3. How to calculate the present worth of a sum due in six months at 8% p.a. simple interest?
4. How do I find the present worth of a sum that will be received in six months at 8% p.a. simple interest, with the sum amounting to Rs 10920?
5. What is the current value of Rs 10920 due in six months at an 8% p.a. simple interest rate?