Q:

# Match the following equation to the correct situation.30%(b - 18) = 30%b - 5.4 A. Last month's electricity bill was 5.4 kW-h less than 30% of this month's bill. B. The number of songs available for download from 30% of b artists. C. The number of cups of coffee thrown away by 30% of b senators during 5.4 speeches. D. The amount of chili eaten from 30% of 5.4 less than b bowls.

Accepted Solution

A:
Answer:A.  Last month's electricity bill was 5.4 kW-h less than 30% of this month's bill.Step-by-step explanation:The given expression is:$$30\%(b-18)=30\%b-5.4$$The above expression tells us that 30% is of the quantity 'b' and 5.4 is being subtracted from the result of the percentage.Choice A:If we consider the present month's bill as 'b'. Then 30% of present month's bill can be represented as 30% of b = 30%b.Now, if the previous month's bill is 5.4 kW-h less than 30% of this month's bill, then this statement can be represented as:Previous bill = 30% of Current bill - 5.4 = $$30\%b-5.4$$Hence, choice A justifies the given expression.Choice B:The expression for choice B could be number of songs available for download from 30% of  'b' artists is $$30%b$$.Choice C:5.4 speeches doesn't make any sense.Choice D:5.4 less than 'b' bowls mean $$b-5.4$$. Now, 30% of this is $$30%(b-5.4)=30%b-30%(5.4)$$. This is also not the correct expression.Therefore, only choice A is the correct justification of the given expression.