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sarahbobarah
Sep 18, 2008, 06:55 PM
Hello! I've been working on this problem for a while and still can't seem to work it out. I would greatly appreciate any help I can get:

Question:
Of three agricultural plots, one has high acidity in soil, one low, and one moderate. One plot will be randomly selected for planting beans, and then another plot will be randomly selected for planting peppers.

a) Make a tree diagram to list all possible assignments
b) What is the probability that peppers get assigned to a plot of low or moderate acidity?
c) What is the probability that one of the crops is assigned to high and the other to low acidic soil?


I tried anwering the questions on my own and just want feedback as to whether they are correct.

Assuming, high acidity (H), low acidity (L), moderate acidity (M), Beans (B), Peppers (P) my answers are:

a) H ---- B or P , L---B or P, M--- B or P (on paper its just two lines coming out as B or P)

b) Probability ( LP or MP) = 2/3

c) I didn't know how to do this one


I appreciate the help!

ebaines
Sep 19, 2008, 01:25 PM
Not sure what a tree diagram is, but if you wrote out all possibilities you would see that there are 6:

HB, MP
HB LP
MB, HP
MB, LP
LB, HP
LB, MP

From this you can see that your answer to (b) is correct, since 4 of the 6 possibilities have either LP or MP.

For (c), just count up the number of times that one crop has a H and the other an L, and divide by 6. Alteratively, you can think through the opposite problem - what is the probability that one of the crops is planted in M, and then subtract that probability from 1.

sarahbobarah
Sep 19, 2008, 04:09 PM
Hello ebaines. Thank you very much for your help. I greatly appreciate it. Take care!