Question

A jar contains 6 red marbles numbered 1 to 6 and 4 blue marbles numbered 1 to 4. A marble is drawn at random from the jar. Find the probability of the given event. Please enter your answer as a decimal rounded to two places. (a) The marble is red Your answer is : (b) The marble is odd-numbered Your answer is : (c) The marble is red or odd-numbered

Answer 1

Explanation:

A

The marble is red. There are 6 red marbles out of ten. So the answer is

6/10 = 0.60

B

Red: 1 3 5

Blue: 1 3

So there are 5 ways that you can draw an odd number. The problem is that they are not evenly distributed.

Red: 1/2 * 3/6 = 1/4 = 0.25

Blue: 1/2 * 2/4 = 0.25

Red + blue = 1/4 + 1/4 = 1/2

You could have gotten 1/2 by taking 5/10 but that won't always work.

C