Another probability question.... (1 Viewer)

[movie_detective]

Greatly appreciated if anyone would answer this question:

In a certain strain of rose seeds, the probability that a seed will produce a purple flower is 1/3. Determine the least number of seeds that Must be planted in order that the probability of obtaining at least one purple flower exceeds 0.9.

My answer was six.....

 

[_pikachu]

whats the answer?
my answer was also 6
5th time = 0.86
6th time = 0.91

 

[movie_detective]

Not really sure what the answer is. Its from a trial paper book and my teacher only provided the questions to do. Since we reached the same answer , probably correct .

 

[zeebobDD]

yeap answer is 6

(2/3)^n > 0.1 logging both sides gives n >5.6
therefore n =6

 

[get_back23]

yeap answer is 6

(2/3)^n > 0.1 logging both sides gives n >5.6
therefore n =6

SOrry, why > than 0.1?

because if its greater, then 1- 0.11 will be smaller than 0.9

 

[Timske]

SOrry, why > than 0.1?

because if its greater, then 1- 0.11 will be smaller than 0.9

It should be (2/3)^n < 0.1

 

[_pikachu]

can someone do it step by step?
i think i did it the long way

 

[zeebobDD]

can someone do it step by step?
i think i did it the long way

sorry it should be < typo there,

so the probability that it won't seed is 2/3, and that is 1-0.9 = 0.1

say theres n number of flowers for it to exceed 0.9

let (2/3)^n < 0.1 n Ln(2/3) < Ln(0.1)

so n > Ln(0.1) / Ln(2/3)