4. In a 50 question multiple choice test, there were four choices for each question; A, B, C and D.
What is the experimental probability that a
randomly selected question will have correct
answer as C?

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?