Multiply the equation:
The solution set is the same, because multiplying both sides of an equation by a non-zero number doesn't change the solution set. In fact, if you rewrite the equation as
Multiplying this by 3 (or whatever number, for all it matters) gives
Now, a product is zero if and only if at least one of the factor is zero. So, either or
Since the first is clearly impossible, the second one must be true, which is the original equation.
The best firm for the Appliance manufacturer for the repair work is Firm 2 .
In the question ,
it is given that ,
An appliance manufacturer wants to contract with a repair shop to handle authorized repairs in Indianapolis .
The acceptable range of the repair time is 50 minutes to 90 minutes.
the mean repair time for firm 1 = 74 minutes and standard deviation of 4 minutes .
the mean repair time for firm 2 = 72 minutes and standard deviation of 5.1 minutes .
the range is calculated using the formula
Range = Mean ± Standard Deviation
So , for firm 1 ,
the Range = 74 ± 4
= 74 4 and 74 - 4
= 78 and 70
the range for firm 2 is
= 72 ± 5.1
= 72 5.1 and 72 - 5.1
= 7.1 and 66.9
The second company has a lower range and it should be preferred .
Therefore , The best firm for the Appliance manufacturer for the repair work is Firm 2 .
Learn more about Standard Deviation here
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