Question

A bucket contains 3 small red blocks, 5 small yellow blocks, 5 large yellow blocks and 7 large red blocks. If a block is drawn randomly, what is the probability that the block is yellow, given that it is one of the large blocks?

Answer 1

P = 5/12 = 0.42

Explanation:

In the bucket we have:

3 small red blocks

5 small yellow blocks

5 large yellow blocks

7 large red blocks

Ok, now we know that we draw one of the large blocks, and we want to find the probability that the block is yellow.

The probability will be equal to the quotient between the number of larger yellow blocks (5) and the total number of large blocks (5 + 7 = 12) (we only care for the large blocks because we start by assuming that we draw one of these)

Then the probability is:

P = 5/12 = 0.42