After driving 175 miles in the plains, car travles up a hill at 28 miles/hr. If the total distance covered in the plains and the
1 answer:
Answer:
3.5 hours was taken by the journey in the hills.
Step-by-step explanation:
Total of 273 miles.
In the plains, 175 miles.
The rest(x), on the hills.
So
175 + x = 273
x = 273 - 175
x = 98
98 miles in the hills, at the speed of 28 miles/hr.
To find the time, we can solve a rule of three.
1 hr - 28 miles
x hrs - 98 miles
3.5 hours was taken by the journey in the hills.
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Answer:
a) 0.1587 (or 15.87%)
b) 0.0478 (or 4.78%)
c) 0.7935 (or 79.35%)
Step-by-step explanation:
Find the following probabilities:
(a) the thickness is less than 3.0 mm
We need to find the area under the Normal curve with a mean of 4.5 mm and a standard deviation of 1.5 mm to the left of 3 mm
<h3>(See picture 1 attached) </h3>We can do that with the help of a calculator or a spreadsheet.
<em>In Excel use </em>
<em>NORMDIST(3,4.5,1.5,1) </em>
<em>In OpenOffice Calc use </em>
<em>NORMDIST(3;4.5;1.5;1) </em>
and we get the value 0.1587 (or 15.87%)
(b) the thickness is more than 7.0 mm
Now we need the area to the right of 7 (1 - the area to the left of 7)
<h3>(See picture 2 attached) </h3><em>In Excel use </em>
<em>1-NORMDIST(7,4.5,1.5,1) </em>
<em>In OpenOffice Calc use </em>
<em>1-NORMDIST(7;4.5;1.5;1) </em>
and we get the value 0.0478 (or 4.78%)
(c) the thickness is between 3.0 mm and 7.0 mm
We are looking for the area between 3 and 7
<h3>(See Picture 3) </h3>Since the area under the Normal equals 1, we have
Area to the left of 3 + Area between 3 and 7 + Area to the right of 7 = 1
Hence,
0.1587 + Area between 3 and 7 + 0.0478 = 1
and
Area between 3 and 7 = 1 - 0.1587 - 0.0478 = 0.7935 (or 79.35%)
