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2 years ago

If you choose one card from a standard deck, what is the probability that the card is either red or a king?

2 answers:

5 0

$|\Omega|=52\\ |A|=\underbrace{26}_{\text{red}}+\underbrace{4}_{\text{king}}-\underbrace{2}_{\text{red king}}=28\\\\ P(A)=\dfrac{28}{52}=\dfrac{7}{13}\approx54\%$

Maksim231197 [3]2 years ago

3 0

Answer:

C) 7/13

Step-by-step explanation:

You might be interested in

Is 120% less than, more than or equal to 1

kati45 [8]

120% is the same as 120/100

Divide 120 with 100

120/100 = 1.2

1.2 > 1 ∴ 120% is 'more than' 1

hope this helps

6 0

2 years ago

The angle θ lies in Quadrant II. sinθ=3/4 What is cosθ ?

Elden [556K]

Hello from MrBillDoesMath

Answer:

[email protected] = - sqrt(7)/ 4

which is choice B

Discussion:

This problem can be solved by drawing triangles and looking at ratios of sides or by using the trig identity:

([email protected])^2 + (sin2)^2 = 1

If [email protected] = 3/4 , the

([email protected])^2 + (3/4)^2 = 1 => (subtract (3/4)^2 from both sides)

([email protected])^2 = 1 - (3/4)^2 = 1 - 9/16 = 7/16

So...... taking the square root of both sides gives

[email protected] = +\- sqrt(7)/ sqrt(16) = +\- sqrt(7)/4

But is [email protected] positive or negative? We are told that @ is in the second quadrant and cos(@) is negative in this quadrant, so our answer must be negative

[email protected] = - sqrt(7)/ 4

which is choice B

Thank you,

Mr. B

4 0

3 years ago

An English professor assigns letter grades on a test according to the following scheme. A: Top 15% of scores B: Scores below the

lisabon 2012 [21]

Answer:

59 to 66

Step-by-step explanation:

Mean test scores = u = 74.2

Standard Deviation = $\sigma$ = 9.6

According to the given data, following is the range of grades:

Grade A: 85% to 100%

Grade B: 55% to 85%

Grade C: 19% to 55%

Grade D: 6% to 19%

Grade F: 0% to 6%

So, the grade D will be given to the students from 6% to 19% scores. We can convert these percentages to numerical limits using the z scores. First we need to to identify the corresponding z scores of these limits.

6% to 19% in decimal form would be 0.06 to 0.19. Corresponding z score for 0.06 is -1.56 and that for 0.19 is -0.88 (From the z table)

The formula for z score is:

$z=\frac{x-u}{\sigma}$