Answer:
a) 
b) 
Explanation:
Previous concepts
The cumulative distribution function (CDF) F(x),"describes the probability that a random variableX with a given probability distribution will be found at a value less than or equal to x".
The exponential distribution is "the probability distribution of the time between events in a Poisson process (a process in which events occur continuously and independently at a constant average rate). It is a particular case of the gamma distribution".
Part a
Let X the random variable of interest. We know on this case that 
And we know the probability denisty function for x given by:
In order to find the cdf we need to do the following integral:
Part b
Assuming that 
, then the density function is given by:
And for this case we want this probability:
And evaluating the integral we got:
The answer is choice C
Explanation:
As during construction ,the site is cleared for all debris before laying out the foundation. Even the sewer lines are dug out .
So it will be useful for the construction crews to connect the pipes to the sewer lines before the foundation is poured.
But usually the steps take in construction activity is:- first the site is cleared for the foundation to be poured and once the foundation wall is set , then all utilities , including plumbing and electrical activities are done.,
After this process is over, the city inspector comes to check whether the foundation has been laid down as per the code of construction.
Only after that the rest of the construction activity follows through.
Answer: Electric current originates from positively charged protons negatively charged electrons of an atom.
Explanation:
The movement of ions (positive or negative) from one point to another is called electric current.
An atom has three sub-atomic particles. These are protons, neutrons and electrons.
Protons are positively charged, neutrons have no charge and electrons are negatively charged. Protons and neutrons reside inside the nucleus of an atom whereas electrons revolve around the nucleus.
So, protons and electrons are responsible for originating electric current form an atom as these are the charged particles.
Thus, we can conclude that electric current originates from positively charged protons negatively charged electrons of an atom.
Batter boards (or battre boards, Sometimes mispronounced as "battle boads") are temporary frames, set beyond the corners of a planned foundation at precise elevations. These batter boards are then used to hold layout lines (construction twine) to indicate the limits (edges and corners) of the foundation.
