Neptunes average distance from the sun is 4.503x10^9 km. Mercury’s average distance from the sun is 5.791 x 10^7 km. About how many times farther from the sun is Neptune than mercury right answer in scientific notation

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)