Greatest common factor/least common multiple of 60 and 84? i used the, "ladder method" and i ended up getting 420 as my answer for the lcm, and 12 as my answer for the gcf.
can someone check this for me and see if it's correct?

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 california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.