correct answer is: c) ₹ 768

Explanation

Here,
Principal = ₹ 600 _{[‘sum’ means ‘principal]}
Amounts = ₹ 720
Time = 4 years
We know, S.I. = (Amounts – Principal)
\therefore S.I. =₹\left(720-600\right)
\rightarrow S.I. = ₹ 120
We also know, S.I. =\frac{p\times t\times r}{100}
\therefore120=\frac{600\times4\times r}{100}
\rightarrow2400r=12000 _{[cross multiply]}
\rightarrow r=\frac{12000}{2400}
\rightarrow\ r = 5 %
\therefore The rate of interest is 5 %.
If the interest increased 2 % then the interest will be \left(5+2\right) % or 7 %
Amount = (Principle + S.I.)
Or, Amount =\left(p+\frac{p\times t\times r}{100}\right) _{[use S.I. formula]}
According to the new rate of interest,
Amount =₹600+\left(\frac{600\times4\times7}{100}\right)
\rightarrow Amount =₹\left(600+\frac{16800}{100}\right)
\rightarrow Amount =₹\left(\frac{60000+16800}{100}\right) _[L.C.M=100]
\rightarrow Amount =₹\frac{76800}{100}
\therefore Amount = ₹ 768
\therefore Increased 2 % interest rate the amount will be ₹ 768 .
Ans: The amount will be ₹ 768 .

An alternative phrasing for this particular query is:
1. If a sum of ₹600 grows to ₹720 in 4 years, what will be the new amount if the interest rate is increased by 2%?
2. Calculate the final amount when a principal sum of ₹600, growing to ₹720 in 4 years, experiences a 2% increase in the interest rate.
3. In case the interest rate is raised by 2%, what will be the total amount if an initial sum of ₹600 becomes ₹720 in 4 years?
4. What is the resulting amount if the interest rate on a ₹600 sum, reaching ₹720 in 4 years, is raised by 2%?
5. Find the new amount after increasing the interest rate by 2% for a sum of ₹600 that matures to ₹720 in 4 years.