Mean (μ) = 11.5 feet
Standard deviation (σ) = 1.7 feet
First we need to find the z-score for less than 13.5 feet.
The formula of z-score is : z = (X - μ)/σ
Here X= 13.5, so z =
z = = 1.18
P(X < 13.5) = P(z< 1.18) =P(z< (1.1 + .08)) = 0.8810 (from z-score table)
P(X< 13.5) = 88.1% (for making percentage from decimal, we need to multiply by 100)
So, the probability that a randomly selected tree is less than 13.5 feet tall = 88.1%
Answer:
:1
Step-by-step explanation:
Ratio of height of two cylinders are 3:1
Let C2 has the height x
then height of C1 is 3x
Let r1 is the radius of C1
and r2 is the radius of C2
As given that volume of both are equal
Also we know that formula for the volume of the cylinder is
V= π r²h
for C1
V= π (r1)²h
for C2
V=π (r2)²h
As volume of both are same so equating them
π (r1)²h1 = π (r2)²h2
as h1 =3x and h2=x
putting values
π (r1)²(3x) = π (r2)²(x)
cancelling out π and x from both side of the equation
3(r1)²= (r2)²
Taking square root of both sides give
r1 ( ) = r2
or
r1 : r2 = :1