Answer:
1 1/3
Step-by-step explanation:
To evaluate the probability that the lifespan will be between 1440 and 1465 hours will be given by:
P(1440<x<1465)
using the z-score formula we obtain:
z=(x-μ)/σ
where:
μ=1450
σ=8.5
hence
when x=1440
z=(1440-1450)/8.5
z=-1.18
P(z<-1.18)=0.1190
when x=1465
z=(1465-1450)/8.5
z=1.77
P(z<1.77)=0.9625
hence:
P(1440<x<1465)
=0.9625-0.1180
=0.8445
Answer:
D,0,2,-2
Step-by-step explanation:
2x^5-3x^3-20x=0
x(2x^4-3x^2-20)=0
x=0
or 2x^4-3x^2-20=0
put x²=t
2t²-3t-20=0
-20×2=-40
8-5=3
8×-5=-40
2t²-(8-5)t-20=0
2t²-8t+5t-20=0
2t(t-4)+5(t-4)=0
(t-4)(2t+5)=0
t=4
x²=4
x=2,-2
t=-5/2
x²=-5/2
it gives imaginary root. so real rational roots are 0,2,-2
40.8 ÷ 69.9 = 0.5836909871
58%
