Answer:
Speed of boat in still water = 11 miles per hour.
Step-by-step explanation:
Speed = distance / time
or
Distance= Speed * time
Let s be speed of the boat upstream and r be the speed of the river.
Then
Upstream speed= s- r = 60/6= 10 miles per hour
Downstream speed= s+r= 72/6= 12 miles per hour
Therefore
s-r= 10--------- equation A
s+r= 12--------- equation B
Adding equation A and Eq. b
s-r= 10--------- equation A
<u>s+r= 12--------- equation B </u>
<u>2s = 22 </u>
<u />
or
s= 22/2= 11 miles per hour.
Speed of boat in still water = 11 miles per hour.
Im guessing 21 and 72 are the side lengths for the triangle?
Alright, so since it's a right triangle you can use the Pythagorean theorem or a^2+b^2=c^2
Since i cant see the picture, im going to use some general math <span>so i</span> can figure out if those two sides are the legs or if one of them is the hypotenuse
Alright
so im guessing the side we're trying to find is the hypotenuse
21^2+72^2=c^2
441+5184=c^2
5625=c^2
<span>√5625=c</span>
75=c
The answer is 75, hope i helped!
Answer: 0.8238
Step-by-step explanation:
Given : Scores on a certain intelligence test for children between ages 13 and 15 years are approximately normally distributed with 
and 
.
Let x denotes the scores on a certain intelligence test for children between ages 13 and 15 years.
Then, the proportion of children aged 13 to 15 years old have scores on this test above 92 will be :-
![P(x>92)=1-P(x\leq92)\\\\=1-P(\dfrac{x-\mu}{\sigma}\leq\dfrac{92-106}{15})\\\\=1-P(z\leq })\\\\=1-P(z\leq-0.93)=1-(1-P(z\leq0.93))\ \ [\because\ P(Z\leq -z)=1-P(Z\leq z)]\\\\=P(z\leq0.93)=0.8238\ \ [\text{By using z-value table.}]](https://tex.z-dn.net/?f=P%28x%3E92%29%3D1-P%28x%5Cleq92%29%5C%5C%5C%5C%3D1-P%28%5Cdfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%5Cleq%5Cdfrac%7B92-106%7D%7B15%7D%29%5C%5C%5C%5C%3D1-P%28z%5Cleq%20%7D%29%5C%5C%5C%5C%3D1-P%28z%5Cleq-0.93%29%3D1-%281-P%28z%5Cleq0.93%29%29%5C%20%5C%20%5B%5Cbecause%5C%20P%28Z%5Cleq%20-z%29%3D1-P%28Z%5Cleq%20z%29%5D%5C%5C%5C%5C%3DP%28z%5Cleq0.93%29%3D0.8238%5C%20%5C%20%5B%5Ctext%7BBy%20using%20z-value%20table.%7D%5D)
Hence, the proportion of children aged 13 to 15 years old have scores on this test above 92 = 0.8238
