There was a sample of 500 milligrams of a radioactive substance to start a study. Since then, the sample has decayed by 5.4% each year . Let t be the number of years since the start of the study. let y be the mass of the sample in milligrams write an exponential function showing relation between y and t

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

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?

Let event a = you roll an even number on the first cube. let event b = you roll a 6 on the second cube. are the events independent or dependent? why?