A box contains 7 red marbles, 4 white marbles, and 5 blue marbles. If only white marbles are added to the box, how many must be added to make the probability of drawing a white marble 1/3?

How do i do this? i don’t understand

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.

How many doughnuts are equal to 20 cookies.? 3 apples = 5 bananas6 cookies = 7 apples2 doughnuts = 1 banana