Can someone me in world geography it's a test & i'm in 9th grade

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

On the map below, which of the following rivers is identified by blue? the huang he river the yangtze river the han river the naktong river

The middle east links which two continents? ●asia and europe●europ and africa●africa and asia●africa and australia