False if you take xyou can get answer
1/2 *(a+b)-(a-b)²
a=18, b=14
1/2 *(18+14)-(18-14)²=1/2 *(18+14)-(18-14)²= 1/2*32-4²=16-16=0
answer D
answer B
2 factors have 2 terms: (x+4) and (y+4)
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.
Oh yes, I am very hurrying, yet!
First, you need to choose a yellow marble. That is 6/15.
Next, you need to choose a blue marble. That is 5/14, because 1 yellow marble would have been "chosen" already.
So the probability altogether is 6/15 * 5/14 = 1/7, or about 14%.