This question is incomplete, the complete question is;
Assume the random variable x is normally distributed with mean p = 80 and standard deviation σ = 4.
Find the indicated probability. P(67 < x < 72)
(Round to four decimal places as needed.)
Answer:
the indicated is 0.0222
Step-by-step explanation:
Given the data in the question;
mean μ = 80
standard deviation σ = 4
p ⇒ P ( x -μ / σ )
so
P(67 < x < 72) ⇒ P( 67-80 / 4 ) < P( x -μ / σ ) < P( 72-80 / 4 )
P(67 < x < 72) ⇒ P( -13 / 4 ) < P( x -μ / σ ) < P( -8 / 4 )
P(67 < x < 72) ⇒ P( -13 / 4 < z < -8 / 4 )
P(67 < x < 72) ⇒ P( -3.25 < z < -2 )
⇒ P( z < -2 ) - P( z < -3.25)
Now from z table;
⇒ 0.02275 - 0.00058
P(67 < x < 72) ⇒ 0.02217 ≈ 0.0222 { four decimal places }
Therefore, the indicated is 0.0222
Let Ted be x.
Ed is 7 years older = x + 7
Ed = (3/4)Ted
(x + 7) = (3/4)x
x + 7 = 3x/4
x - 3x/4 = -7
x/4 = -7
x = -28, Ted = -28 years.
(x + 7) = -28 + 7 = -21, Ed = -21 years
Goodness. We had negative numbers for the ages, well does that make sense? No it doesn't.
Our answer is correct. But the sense in the question is lacking. The question has been wrongly set.
<span>We might assume negative ages to mean before they came into the world, before birth! </span>
The answer is A or the 1 selectible option
You just need to look at it from left to right
5x^2+2x-3=0
We can use the quadratic formula:
ax^2+bx+c=0; a=5, b=2, c=-3
x=[-b+-sqrt(b^2-4ac)]/(2a)
x=[-(2)+-sqrt((2)^2-4(5)(-3))]/[2(5)]
x=[-2+-sqrt(4+60)]/10
x=[-2+-sqrt(64)]/10
x=(-2+-8)/10
Two solutions:
x1=(-2-8)/10→x1=(-10)/10→x1=-1
x2=(-2+8)/10→x2=6/10→x2=3/5
Answer: x=-1 and x=3/5
Answer: Options D. x=-1 and F. x=3/5
