If kevin has an equal number of dimes, nickels, and quarters in his piggy bank. he randomly picks a coin, replaces it, and picks another coin. what is the probability that the sum of the two coins picked is at least 30 cents?

2/9
4/9
5/9
1/3
2/3

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?