Graphite is made up of layers of graphene. Each layer of graphene is about 200 200
picometers, or 200×10−12
200
×
10
−
12
meters, thick.

How many layers of graphene are there in a 1.6
1.6
-mm-thick piece of graphite? Write your 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%)