Answer: $44.10
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Work Shown:
5% = 5/100 = 0.05
5% of 42 = 0.05*42 = 2.10
tax = $2.10
total cost including tax = $42 + $2.10 = $44.10
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An alternative is to multiply 42 by 1.05 to get
1.05*42 = 44.10
We get the same answer. The 1.05 refers to 1 + 0.05 where the "1" is 100% and the 0.05 is 5%, so the two combine to 105%, meaning the total cost is 105% of the cost before tax is considered.
