MaxWong

That is complicated. A easier way to do......

No matter how you select the flowers, you must have selected a red flower or a yellow flower, so the probability of selecting a flower(red or yellow) is 1. 

P(Red) + P(Yellow) = 1

I guess you wouldn't have found a turqoise coloured flower out from nowhere? <- That's not funny. You laugh because you sucks.

7/15 + P(Yellow) = 1

P(Yellow) = 1 - 7/15 = 8/15

Sorry I am a bit moody today so that I am not very nice. Even to my father and mother.

Let x be the total number of flowers.

7/x = 7/15

Obviously x = 15.

Number of yellow flowers = Total - Red = 15 - 7 = 8

Probability of selecting a yellow flower is (No. of yellow)/(Total)=8/15

$(\dfrac{3}{8})^4=\dfrac{3^4}{8^4}=\dfrac{81}{4096}$

Same as Guest #1's answer.

Paradox.

Ya :D Did you forgot to login? Who are you?

$\ln(6^{719})\\ =719 \ln 6\\ \approx 1288.2750583749715456$

$-7/9 + 8\\ = -7/9 + 72/9\\ = (72-7)/9\\ = 65/9\\ = 7\;\;2/9$

$\quad 16x^2-49\\ = (4x)^2-7^2\\ = (4x-7)(4x+7)$

$\left(\dfrac{6x^3y^{-7}}{9xy}\right)^{-1}\\ = \dfrac{9xy}{6x^3y^{-7}}\\ = \dfrac{9xy^8}{6x^3}\\ =\dfrac{3y^8}{2x^2}$