The answer is <span>twelve sevenths (12/7)
</span>
x - the job<span>
t - time to do the job x
</span><span>Robin can mow a lawn in 3 hours: x/3 * t
</span><span>Brady can mow the same lawn in 4 hours: x/4 * t
</span><span>If they work together, the total work will
be the sum of their speeds:
</span>x = x/3 * t + x/4 * t = (x/3 + x/4)*t = (4x/12 + 3x/12) * t = 7x/12 * t
x = 7x/12 * t
Divide both sides by x:
x/x = 7x/12 * t/x
1 = 7/12 t
t = 1 : 7/12
t = 12/7
Answer:
a) P ( 3 ≤X≤ 5 ) = 0.02619
b) E(X) = 1
Step-by-step explanation:
Given:
- The CDF of a random variable X = { 0 , 1 , 2 , 3 , .... } is given as:
Find:
a.Calculate the probability that 3 ≤X≤ 5
b) Find the expected value of X, E(X), using the fact that. (Hint: You will have to evaluate an infinite sum, but that will be easy to do if you notice that
Solution:
- The CDF gives the probability of (X < x) for any value of x. So to compute the P ( 3 ≤X≤ 5 ) we will set the limits.
- The Expected Value can be determined by sum to infinity of CDF:
E(X) = Σ ( 1 - F(X) )
E(X) = Limit n->∞ [1 - 1 / ( n + 2 ) ]
E(X) = 1
Answer:
15.1
Step-by-step explanation:
29.34
-14.24
---------
15.10
Simplifying
25x + -15 = 2y
Reorder the terms:
-15 + 25x = 2y
Solving
-15 + 25x = 2y
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '15' to each side of the equation.
-15 + 15 + 25x = 15 + 2y
Combine like terms: -15 + 15 = 0
0 + 25x = 15 + 2y
25x = 15 + 2y
Divide each side by '25'.
x = 0.6 + 0.08y
Simplifying
x = 0.6 + 0.08y
We know that
Inverse Variation is a<span> relationship between two variables in which the product is a constant
so
let
x------> a pitch of a musical instrument
y------> </span><span>the wavelength
x*y=k
find the value of k
for x=</span><span>220 hertz y=3 ft
</span><span>x*y=k
220*3=k
k=660
</span>for x=165 hertz y=4 ft
x*y=k
165*4=660
k=660<span>
the answer part a) is
</span><span>the type of variation between pitch and wavelength is an inverse variation
</span>
part b) <span>What is the pitch when the wavelength is 5 feet?
x=?
y=5 ft
k=660
x*y=k------> solve for x
x=k/y----------> x=660/5-----> x=132 hertz
the answer Part b) is
132 hertz</span>
