A bag contains 20 black balls and 10 white balls. One ball is drawn at random. What is the probability that the ball drawn is white? Choose the correct choice.
A) 2/5 B) 5/7 C) 1/2 D) 1/4 E) 1/3
Total number of balls = 20+10= 
<gadget id="calculator">20+10</gadget>
<output>30</output>
30   no. of white balls= 10   probability of drawing a white ball = 10/30 = 1/3   Answer is 1/3
<result>E</result>
A bag contains 20 black balls and 10 white balls. One ball is drawn at random. What is the probability that the ball drawn is white?