First, the formula for the average of a data set must be defined. It is calculated by adding all the numbers in the data set and then dividing the sum by the number of data. In this case, the average is set to be equal to $400 with the total number of data being 3, with the September expenditure set as an unknown, x. The equation is then set-up to be: 400 = (401.5 + 250 + x)/3. Thus, Joshua can spend as much as $ 548.5 to be able to have the same average as in his second quarter expenditure.
The best way to answer this is to find counterarguments for each answer to eliminate them as a possibility. ab doesn't have to be an integer, 2.5*3=7.5 . That's also not an imaginary number so that's out. And that's also not an irrational number so that's out too. Only choice left is rational number.
Answer:
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Step-by-step explanation:

Because

is singular, we have

from which it follows that either

or

.