Answer:
the probability that at least one envelope is a yellow envelope is 16/21
Step-by-step explanation:
The probability that at least one envelope is a yellow envelope is P(Y);
P(Y) = 1 - P(Y)'
P(Y)' is the probability that no envelope is a yellow envelope.
Given;
red envelope = 1
blue envelopes = 3
green envelopes = 2
yellow envelopes = 3
Total = 9
Number of non-yellow envelope = 9 -3 = 6
(6 envelope are not yellow)
P(Y)' = P1 × P2 × P3
Since there is no replacement;
P(Y)' = 6/9 × 5/8 × 4/7
P(Y)' = 5/21
From equation 1;
P(Y) = 1 - 5/21
P(Y) = 16/21
the probability that at least one envelope is a yellow envelope is 16/21.
There are 10 rooms per floor if there are 30 floors then there are 300 rooms
Answer: 4x^2 + 6xy + 2y^2
Step-by-step explanation:
(2x + y)(2x + 2y) =
2x*2x + 2x*2y + y*2x + y^2y =
4x^2 + 4xy + 2xy + 2y^2 =
4x^2 + 6xy + 2y^2
bearing in mind that perpendicular lines have negative reciprocal slopes, so
![\bf \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}~\hspace{10em}\stackrel{slope}{y=\stackrel{\downarrow }{-\cfrac{1}{3}}x-1} \\\\[-0.35em] ~\dotfill](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7B%7Cc%7Cll%7D%20%5Ccline%7B1-1%7D%20slope-intercept~form%5C%5C%20%5Ccline%7B1-1%7D%20%5C%5C%20y%3D%5Cunderset%7By-intercept%7D%7B%5Cstackrel%7Bslope%5Cqquad%20%7D%7B%5Cstackrel%7B%5Cdownarrow%20%7D%7Bm%7Dx%2B%5Cunderset%7B%5Cuparrow%20%7D%7Bb%7D%7D%7D%20%5C%5C%5C%5C%20%5Ccline%7B1-1%7D%20%5Cend%7Barray%7D~%5Chspace%7B10em%7D%5Cstackrel%7Bslope%7D%7By%3D%5Cstackrel%7B%5Cdownarrow%20%7D%7B-%5Ccfrac%7B1%7D%7B3%7D%7Dx-1%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill)
so we're really looking for a line whose slope is 3 and runs through (1,5)
