We have 4 plants, so we can arrange them in 4! ways = 24 waysHey, why is it 4! line all plants are different?
You have 2 white and 2 red. I assumed that you cannot distinguish between them and I counted the total amount as:
(4!)/(2!2!)
Why did you count it as you have 4 different plants?
GreenlightTestPrep wrote:
Carcass wrote:
A gardener is going to plant 2 red rosebushes and 2 white rosebushes. If the gardener is to select each of the bushes at random, one at a time, and plant them in a row, what is the probability that the 2 rosebushes in the middle of the row will be the red rosebushes?
A. 1/12
B. 1/6
C. 1/5
D. 1/3
E. 1/2
As with many probability questions, we can also solve this using
counting techniques. P(2 middle are red) = (
# of outcomes with 2 red in middle)/(
total number of outcomes)
Label the 4 bushes as W1, W2, R1, R2
total number of outcomesWe have 4 plants, so we can arrange them in 4! ways = 24 ways# of outcomes with 2 red in middleIf we consider the possibilities here, we can LIST them very quickly:
- W1, R1, R2, W2
- W1, R2, R1, W2
- W2, R1, R2, W1
- W2, R2, R1, W1
So, there are 4 outcomes with 2 red in middleP(2 middle are red) =
4/
24= 1/6
Answer: B
Cheers,