I don't understand Can you type it again?
Simply divide 3 by 0.7,

Or ≈ 4.28571 which is ≈ 4 years.
Answer:

Step-by-step explanation:
We were given the slope formula;

This line is vertical if the denominator is zero.
That is when 
This implies that;

Justification;
When
, then, the line passes through;
and 
The slope now become

The equation of the line is

This implies that;




... This is the equation of a vertical line.
Answer:
a) P(t>3)=0.30
b) P(t>10|t>9)=0.67
Step-by-step explanation:
We have a repair time modeled as an exponentially random variable, with mean 1/0.4=2.5 hours.
The parameter λ of the exponential distribution is the inverse of the mean, so its λ=0.4 h^-1.
The probabity that a repair time exceeds k hours can be written as:

(a) the probability that a repair time exceeds 3 hours?

(b) the conditional probability that a repair takes at least 10 hours, given that it takes more than 9 hours?
The exponential distribution has a memoryless property, in which the probabilities of future events are not dependant of past events.
In this case, the conditional probability that a repair takes at least 10 hours, given that it takes more than 9 hours is equal to the probability that a repair takes at least (10-9)=1 hour.


Answer:
6xy^3 +12xy^2 z
Step-by-step explanation:
3xy^2 (2y+4z)
Multiply
3xy^2 * 2y + 3xy^2 *4z
common factors
3xy^3 +3xy^2 *4z
Multiply
6xy^3 +12xy^2 z