If you start with 100% of a substance, what percentage of the substance would you have after 3 half-lives?

In north america, most winter storms form when cold, dry air from interacts with warm, moist air from

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

Air masses are characterized by various properties including temperature humidity air pressure and wind speed. which of the following air masses is associated with low relative humidity and high air temperature ?