Answer: the probability that a randomly selected dropout is white is 0.4902%
Explanation:
According to the provided information,
 8.6% of high school dropouts are in the age bracket of 16 to 17 years old.
 Then 5.7% of the high school dropouts that are 16 to 17 years old are whites.
 Therefore, the probability that a randomly selected dropout is white = 
 5.7% of 8.6% = 0.4902%.
 For clarity sake, we can assume that there are 3000 students in the high school.
 8.6% are dropouts :
 8.6/100 × 3000 = 258 total dropouts.
 Now, suppose 5.7% of the total dropouts in that school are whites, therefore the number of white dropouts in the school is:
 5.7/100 × 258
 = 14 white dropouts.
 We can also achieve this by multiplying the two percentages by the total number of students in the school
 i.e 8.6% × 5.7% × 3000
 = 14 whites dropouts
 This affirms that the probability that a randomly selected dropout is white = 
 5.7% × 8.6% = 0.4902%