-2/5 + 1/2 please help guys I really need it

Ineed to learn how to solve this problem

Janet drove 300 miles in 4.5 hours. write an equation to find the rate at which she was traveling

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.