fix: correct typo in README

Author: dhokabhoomi

README.md

@@ -1,14 +1,16 @@
-# Introduction to Git and GitHub
+# Simple Interest Calculator
 
-## Simple Interest Calculator
+This is a simple bash script to calculate **Simple Interest** given the principal amount, annual rate of interest, and time period in years. It is intended as a beginner-friendly open-source project to demonstrate basic shell scripting and Git/GitHub workflows.
 
-A calculator that calculates simple interest given principal, annual rate of interest and time period in years.
 
-```
+## Input and Output
+
+```bash
 Input:
-   p, principal amount
-   t, time period in years
-   r, annual rate of interest
-Output
-   simple interest = p*t*r
+p - Principal amount
+t - Time period in years
+r - Annual rate of interest (%)
+
+Output:
+simple interest = (p _ t _ r) / 100
 ```