Radhikabought a house for Rs. 5, 20,000, and she spent Rs.80,000 on its repair. She sold it for Rs.6, 40,000. Find her profit or loss percent.

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?