Question

You plant a fruit Tree. The probability that the tree will survive its first winter is 0.8. If it survives the first winter, the probability that the tree will have fruit by its fourth year is 0.6. What is the probability that the tree will bear fruit by its fourth year??

Answer 1

(show all work)

Answer 2

i think if u add 0.8 and 0.6 and divide by 2 u will get the answer but i am not sure

Answer 3

\[\frac{ 0.8+0.6 }{ 2 }\]

Answer 4

i need someone who's sure of the answer :s

Answer 5

1.4/2
7

Answer 6

sorry 0.7

Answer 7

Ignore that.

Answer 8

So the concept you have to use here is that if I have two events, A and B, the probability that they will both happen, P(A&B), is P(A)*P(B).

So for example, the probability to flip a heads and then roll a 6 on a die is
P(H)*P(6) = (1/2)(1/6) = (1/12)

Answer 9

i never learned that before- can you help me with that??

Answer 10

Gladly. Do you understand what I'm saying?

Answer 11

kind of, how do you have 2 events?

Answer 12

There are a lot of ways you could have 2 events.

Answer 13

question is not sufficient acc to what asked

Answer 14

I want one thing to happen, and I want a second thing to also happen.
Or I want one thing to happen and then after that, something else to happen.

Answer 15

ok but in my math problem how would you set that up, i don't know which two events to plug into the equation

Answer 16

Don't think of it as plugging into an equation. Slow down, understand the concept I'm explaining to you.

Answer 17

sorry i really didn't understand this question @SmoothMath and @erica123

Answer 18

If I have two events, and I want to know the probability that they will BOTH happen, I simply multiply the probability that either of them will happen.

What's the probability that I will flip heads twice?
The first event is that I'll flip heads, and the second event is that I'll flip heads again.
What's P(H), the probability of flipping heads once? It's (1/2), or .5
So, what's the probability that I will flip heads twice?
.5*.5 = .25

Answer 19

@Bhagyashree that's okay, buddy.

Answer 20

ok so once flipping the coin 1/2 and again if you flip it twice its another 1/2 so its 0.4 i understand that concept in this problem but in my problem its confusing :s

Answer 21

oops 0.25!

Answer 22

Well, not .4
It would be (1/4) or .25
Right =)

Answer 23

yes my mistake i typed it wrong

Answer 24

So, if you understand that concept, then you can apply it to this problem.

Answer 25

but then there's two different numbers, 0.8 and 0.6 and it says in 4 years i dont know how to do that one

Answer 26

We want to know the probability that the tree will bear fruit in its 4th year, but to do that, it has to survive its first year.
So what is the probability it will survive and then ALSO bear fruit?

Answer 27

0.6?

Answer 28

No.

Answer 29

i dont know how to do it?

Answer 30

Yes you do. 2 events. What's the probability that they will both happen?

Answer 31

It's exactly the same as the examples I gave you.

Answer 32

i dont know how to do it with this one do i multiply the 0.6 or the 0.8?

Answer 33

...
Your question makes no sense.

Answer 34

sorry :( which one do i use to figure out which ones will happen?

Answer 35

like do i use the probability if it survives the first winter (0.8) or in 4 years (0.6)

Answer 36

Erica, let me just give you like... a bunch of simple examples and see if you can catch on.

The probability of flipping heads and then flipping heads is
.5 * .5 = .25

The probability of rolling a 1 and then flipping heads is
(1/6) * (1/2) = (1/12)

The probability of flipping a heads and then rolling an even number is
(1/2) * (3/6) = (3/12) = .25

The probability of pulling the ace of spades and then rolling a 3 is
(1/52) * (1/6) = (1/312)

Answer 37

Imagine that the probability of someone speeding being pulled over is .3, and the probability of someone who's been pulled over getting a ticket is .7.
If I speed, the probability of me being pulled over and THEN getting a ticket is
.3 * .7 = .21

Answer 38

ok so the probability of the tree surviving and bearing fruit is
0.6*0.8= .48?

Answer 39

im not sure if thats right

Answer 40

Imagine that the probability of me forgetting to shower each day is .14. If I don't shower, the probability of someone noticing is .42.
The probability of me forgetting to shower and THEN have someone notice is
.14 * .42 = .00588

Answer 41

That's right.
It has to survive its first winter and THEN bear fruit.
.8*.6

Answer 42

ok i think i sorta got it now wait so that the answer? or is there more to it

Answer 43

That's it. Super simple.

Answer 44

If you have 2 events, and you want to know the probability of BOTH of them happening, just multiply 'em up!

Answer 45

ok thanks so much! um i really dont want to ask you this but i have 3 others like this but are somewhat different can you please help me on that?

Answer 46

Surely. Make sure you try on your own first.

Answer 47

ok sure so do i just post them here or make a new question thread?

Answer 48

Traditionally, posting a new question is the thang.

Answer 49

ok