What is the probability of getting an even number on a single roll of a number cube if you roll a 3 or greater.
My answer: is 1/3 because there are only two numbers that are even and greater than 3 on the number cube.
Teacher marked this as wrong. How did I mess this one up?
this sure looks like a "conditional" probability.
in general
P(A│B) = P(A AND B)/P(B)
read: P(A│B) as "the prob of A given B"
so let A be (even number)
let B be (greater or equal to 3)
so P(A and B) = 2/6 = 1/3
P(B) = 4/6 = 2/3
so P(A│B) = (1/3)/(2/3) = 1/2
To find out where you made a mistake, let's break down the problem step by step.
Step 1: Determine the sample space.
The sample space is the set of all possible outcomes. In this case, when rolling a number cube, the sample space consists of the numbers 1, 2, 3, 4, 5, and 6.
Step 2: Determine the favorable outcomes.
To determine the favorable outcomes, we need to identify the even numbers greater than 3 in the sample space. In this case, the numbers 4 and 6 are even and also greater than 3.
Step 3: Calculate the probability.
To calculate the probability, we need to divide the number of favorable outcomes by the total number of possible outcomes.
Thus, the probability is given by: favorable outcomes / total outcomes.
Favorable outcomes: 2 (numbers 4 and 6)
Total outcomes: 6 (numbers 1, 2, 3, 4, 5, and 6)
So, the probability of getting an even number on a single roll of a number cube if you roll a 3 or greater is 2/6 or simplified, 1/3.
Therefore, your initial answer of 1/3 is indeed correct. It seems like there may have been a misunderstanding or marking error by your teacher. You could consider discussing this issue with your teacher to clarify the situation.
To find the probability of getting an even number on a single roll of a number cube if you roll a 3 or greater, we need to determine the total number of favorable outcomes divided by the total number of possible outcomes.
In this case, the favorable outcomes are the even numbers greater than 3, which are 4 and 6. Therefore, there are 2 favorable outcomes.
The possible outcomes when rolling a number cube that is 3 or greater are 3, 4, 5, and 6. Hence, there are 4 total possible outcomes.
So, the probability can be calculated as: favorable outcomes/total outcomes = 2/4 = 1/2.
Since you mentioned that the teacher marked your answer as wrong, it's possible that there was an error in understanding the question or presenting the answer. It might be best to consult with your teacher to clarify any confusion and understand what mistake might have been made.