A certain star is 3.86×10 to the 9th power km in diameter. What is the measure of its radius?

Me because some of question i don’t understand

Acar travels at an average speed of 52 miles per hour. how long does it take to travel 299 miles

Nour and rana are shopping for a christmas tree. they are deciding between 2 22 different types of trees (real and fake) and 4 44 colors for the ornaments (white, silver, gold, and purple). they each created a display to represent the sample space of randomly picking a type of tree and a color for the ornaments. whose display correctly represents the sample space?