A man borrowed Rs 6000 from a bank at a 6% annual interest rate. What is the amount he must pay after two and a half years?

Given, Principal amount P = Rs. 6000

Time period T = 2$\frac{1}{2}$ years = $\frac{5}{2}$ years

Rate of interest R = 6% p.a.

Formula:

Simple interest = $\frac{\mathrm{P} \times \mathrm{T} \times \mathrm{R}}{100}$

Calculation:

SI = $\frac{6000 \times {\displaystyle \raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \times 6}{100}$

SI = Rs. 900

Amount = Principal amount + Interest

A = Rs. 6000 + 900

A = Rs. 6900

Hence, the correct answer is Rs. 6900.