A box contains 4 red, 3 green, and 2 blue marbles. If a marble is drawn and it i
Practice Questions
Q1
A box contains 4 red, 3 green, and 2 blue marbles. If a marble is drawn and it is green, what is the probability that the next marble drawn is red?
0.4
0.5
0.6
0.3
Questions & Step-by-Step Solutions
A box contains 4 red, 3 green, and 2 blue marbles. If a marble is drawn and it is green, what is the probability that the next marble drawn is red?
Correct Answer: 0.5
Step 1: Count the total number of marbles in the box. There are 4 red, 3 green, and 2 blue marbles. So, total = 4 + 3 + 2 = 9 marbles.
Step 2: If a green marble is drawn, we remove it from the box. Now, we have 4 red, 2 green, and 2 blue marbles left.
Step 3: Count the remaining marbles. After drawing a green marble, the total remaining marbles = 4 red + 2 green + 2 blue = 8 marbles.
Step 4: Determine how many red marbles are left. There are still 4 red marbles.
Step 5: Calculate the probability of drawing a red marble next. The probability is the number of red marbles divided by the total remaining marbles: Probability = 4 red / 8 total = 0.5.
Conditional Probability – The probability of an event occurring given that another event has already occurred.
Counting Outcomes – Understanding how to count the remaining outcomes after an event has taken place.
