Question

There are 50 marbles of 3 colors: blue yellow and black The probability of picking up a blue marble is 3/10 and that of picking up a yellow marble is 1/2 The probability of picking up a black ball is

• A. 1/5
• B. 1/10
• C. 1/4
• D. 4/5

Answer 1

Answer: (A)

1/5

P(blue)=$\frac{3}{10}=\frac{15}{50},$i.e., there are 15 blue marbles
P(yellow)=$\frac{1}{2}=\frac{25}{50},$i.e., there are 25 yellow marbles
$\therefore$ Number of black marbles=10
$\therefore$ P(black)=$\frac{10}{50}=\frac{1}{5}$