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Marizza181 [45]
3 years ago
10

Working alone, Natalie can clean an attic in 9 hours. Lea can clean the same attic in 8 hours. How long would it take them if th

ey worked together?
Work it out please!!!
A) 5.47 hours
B)3.78 hours
C)4.74 hours
D)4.24 hours
Mathematics
1 answer:
professor190 [17]3 years ago
3 0
(1 attic / 8 hrs) + (1 attic / 9 hrs) = (1 attic / t hrs)

1/8 + 1/9 = 1/t
find common denominator
9/72 + 8/72 = 1/t
17/72 = 1/t
flip or cross multiply
72/17 = t
4.24 hrs = t
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What is the graph of the polynomial function
Nitella [24]
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Note that we have a repeated (double) root at x=3, which is given away by the exponent 2 of (x-3).

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If you'll find the y-value for each of these x-values and plot the resulting points, you should see the shape of the graph.  Draw a rough graph thru these points.  If any doubt remains about what the graph looks like at particular x-values, calculate and plot more points, e. g., at {-2.5, -1.5, ...}.

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3 years ago
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iVinArrow [24]

Answer:

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Explanation:

When you want to compare the means of two samples with different statistics you may use the z-score.

The z-score measures how far a value (data point) is from the mean, in terms of the standard deviation.

The z-score is calculated as:

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<u />

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7 0
3 years ago
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