Answer:
Efficient when the marginal benefits of project = marginal costs of project.
Explanation:
Majority Decision Rule:
Majority decision rule is based on the notion of equality. An alternative is selected which has majority of votes. The simple majority decision rule may generate efficient results if the marginal benefits of a project are equal or greater than the marginal costs of the project.
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:

Answer:
the welding gun liner regulates the shielding gas.
Explanation:
The purpose of the welding gun liner is to properly position the welding wire from the wire feeder till it gets to the nozzle or contact tip of the gun. <em>Regulation of the shielding gas depends on factors such as the speed, current, and type of gas being used. </em>In gas metal arc welding, an electric arc is used to generate heat which melts both the electrode and the workpiece or base metal.
The electric arc produced is shielded from contamination by the shielding gas. The heat generated by the short electric arc is low.