What are the steps? Is there a photo?
7x-15=-2
Move -15 to the rigjt side,
7x=-2+15
7x=13
Divide both sides by 7,
7x/7=13/7
x=13/7
You're going to have to work out the z-scores of both values in each option and see if it makes sense.
n = m + sz
The mean is 20 and the standard deviation is 3.
So let's find try the z-scores of the outer range values and determine their probabilities:
from 14-20:
n = m + sz
20 = 20 + 3z and 14 = 20 + 3z
0 = 3z and -6 = 3z
z = 0 and z = -2
So now using a z-score table, such as the one below, find the probabilities.
z = 0 is easy, it's 0.5
z = -2 is 0.02275
Subtract the smaller from the larger to get the probability of getting in the range:
0.5 - 0.02275 = 0.47725 (so times 1000, you get 477.25, which is not about 340, so this option is wrong)
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Now trying option 2, from 17-29:
n = m + sz
29 = 20 + 3z and 17 = 20 + 3z
9 = 3z and -3 = 3z
z = 3 and z = -1
0.99865 - 0.158655 = 0.839995 (not 680, so not the answer)
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Now trying option 3, from 20-23:
n = m + sz
23 = 20 + 3z and 20 = 20 + 3z
3 = 3z and 0 = 3z
z = 1 and z = 0
0.841345 - 0.5 = 0.341345 (close to 340, so is your answer)
Answer:
A
Step-by-step explanation:
The volume (V) of water in the tank is calculated as
V = lbh (l is length, b is breadth and h is height )
Here l = 80, b = 40 and h = 50 , then
V = 80 × 40 × 50 = 160000 cm³
V ( in litres) = 160000 ÷ 1000 = 160 litres , then
number of times = 160 ÷ 10 = 16
Answer:
5x-2y=12
Step-by-step explanation:
