3. (2.56 x 10^6) x (3.56 x 10^2) =

a. 9.1136 x 10^12
b. 91.136 x 10^8
c. 9.1136 x 10^8
d. 91.136 x 10^12

4. In a recent year, the population of California was about 2.52 x 10^7 people. Its land area is about 4.05 x 10^5 km2. What was the average number of people per square kilometer?

a. 0.62 x 10^5
a. 6.2 x 10^1
a. 0.62 x 10^14
a. 6.2 x 10^9