The Smiths are sending out a batch of holiday cards. Emily signed 2/5 of the cards. Then Josh signed 1/9 of the remaining cards.
1 answer:
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Answer:
A
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
BC² = 9² + 12² = 81 + 144 = 225 ( take the square root of both sides )
BC = = 15 → A
A) 0.9803; 0.4803
B) 32
We calculate the z-score for this problem by using the formula:
Using our formula, we have:
Using a z-table (http://www.z-table.com) we see that the area to the left of, less than, this score is 0.9803.
To find the probability it is between the mean and this, we subtract the probability associated with the mean (0.5) from this:
0.9803 - 0.5 = 0.4803.
To find B, we first find the z-score for this. Using a z-table (http://www.z-table.com) we see that the closest z-score would be 2.33. We then set up our equation as
Multiplying both sides by 0.85 we have
2.33(0.85) = 0.35√n
1.9805 = 0.35√n
Divide both sides by 0.35:
1.9805/0.35 = √n
Square both sides:
(1.9805/0.35)² = n
32 ≈ n
B) 32
We calculate the z-score for this problem by using the formula:
Using our formula, we have:
Using a z-table (http://www.z-table.com) we see that the area to the left of, less than, this score is 0.9803.
To find the probability it is between the mean and this, we subtract the probability associated with the mean (0.5) from this:
0.9803 - 0.5 = 0.4803.
To find B, we first find the z-score for this. Using a z-table (http://www.z-table.com) we see that the closest z-score would be 2.33. We then set up our equation as
Multiplying both sides by 0.85 we have
2.33(0.85) = 0.35√n
1.9805 = 0.35√n
Divide both sides by 0.35:
1.9805/0.35 = √n
Square both sides:
(1.9805/0.35)² = n
32 ≈ n