Answer:
The probability is 0.9211
Step-by-step explanation:
Let's call K the event that the student know the answer, G the event that the student guess the answer and C the event that the answer is correct.
So, the probability P(K/C) that a student knows the answer to a question, given that she answered it correctly is:
P(K/C)=P(K∩C)/P(C)
Where P(C) = P(K∩C) + P(G∩C)
Then, the probability P(K∩C) that the student know the answer and it is correct is:
P(K∩C) = 0.7
On the other hand, the probability P(G∩C) that the student guess the answer and it is correct is:
P(G∩C) = 0.3*0.2 = 0.06
Because, 0.3 is the probability that the student guess the answer and 0.2 is the probability that the answer is correct given that the student guess the answer.
Therefore, The probability P(C) that the answer is correct is:
P(C) = 0.7 + 0.06 = 0.76
Finally, P(K/C) is:
P(K/C) = 0.7/0.76 = 0.9211
Answer:
N=250
Step-by-step explanation:
"twice as many nickels as dimes" means N =2D [eq1]
"collection of nickels and dimes is worth $25" means
5N + 10D = 2500 [eq2]
(To avoid using decimal points, PLZ express everything in cents.)
Substitution (substitute N from eq1 into eq2]:
5(2D) + 10D = 2500
10D + 10D = 2500
20D = 2500
D = 125
N=2D [eq1 again]
N=2(125)
N=250
Check:
Is 5(250) + 10(125) = 2500 ?
1250 + 1250 = 2500 ?
2500 = 2500 ?yes
The inverse will be 2x+3/4 or D in your picture
Answer:
Step-by-step explanation:
Negative sign is outside the parenthesis. So, each term of (4k² - 13k -12) should be multiplied by (-1)
-(4k² - 13k -12) + 5k² - 8k = 4k²*(-1) - 13k*(-1) - 12*(-1) + 5k² - 8k
= -4k² + 13k + 12 +5k² - 8k
Combine like terms,
= -4k² + 5k² + 13k - 8k + 12
= k² + 5k + 12
Like terms are the terms with same variable with same exponent.
(-4k² ) and 5k² are like terms
13k and (-8k) are like terms
Answer:
The answer is C, zero solutions.
Step-by-step explanation:
y = 5/2x + 2
2y = 5x + 8
Multiply 2 to the first equation.
2y = 5x + 4
Compare it with the other equation
2y = 5x + 4
2y = 5x + 8
Cancel 2y and 5x on both sides.
Remaining:
4 = 8
4 ≠ 8. Therefore, the answer is C, zero solutions.
