Question: there are 18 balls in a jar . you take out 3 blue balls without putting them back inside , and now the probability of pulling out a blue ball is 1 / 5 . how many blue balls were there in the beginning ?
A) 12
B) 9
C) 8
D) 7
E) 6
Correct answer: e
Grade: 7 | Topic: Statistics and Probability | Difficulty: Hard | Standard: 7.SP.C.7