I’m thinking it’s A cause the others don’t seem right
Given that mean=3750 hours and standard deviation is 300:
Then:
<span>a. The probability that a lamp will last for more than 4,000 hours?
P(x>4000)=1-P(x<4000)
but
P(x<4000)=P(z<Z)
where:
z=(x-</span>μ)/σ
z=(4000-3750)/300
z=0.833333
thus
P(x<4000)=P(z<0.8333)=0.7967
thus
P(x>4000)=1-0.7967=0.2033
<span>b.What is the probability that a lamp will last less than 3,000 hours?
P(x<3000)=P(z<Z)
Z=(3000-3750)/300
z=-2.5
thus
P(x<3000)=P(z<-2.5)=0.0062
c. </span><span>.What lifetime should the manufacturer advertise for these lamps in order that only 4% of the lamps will burn out before the advertised lifetime?
the life time will be found as follows:
let the value be x
the value of z corresponding to 0.04 is z=-2.65
thus
using the formula for z-score:
-2.65=(x-3750)/300
solving for x we get:
-750=x-3750
x=-750+3750
x=3000</span>
Answer:
A.) 2x - 9x - 30 = -6
Step-by-step explanation:
hello !
to solve this system of equations, first, we substitute the equation 
to the <em>y </em>variable in the equation 
. Therefore, we get:
now, we simplify by multiplying -3 to the variables inside the parenthesis, which, in short, is also called the distributive property. thus, we get:
<h3>
Answer: 8</h3>
Reason:
Replace p with 2 and evaluate.
Think of a cube that is 2 units along each side. It's volume is 2*2*2 = 8 cubic units. Repeated multiplication can be shortened to using exponents.
Another example: 
Answer:
i cant see the picture
Step-by-step explanation:
