Answer:
$67.45
Explanation:
There are a couple of ways you can go at these.
1. Compute the tip, then add that to the bill.
... 15% × $58.65 = $8.7975 ≈ $8.80
... $58.65 + 8.80 = $67.45
2. Compute the effect of adding the tip, then use that result to multiply by the bill amount.
... bill + (15% × bill) = bill × (1 +0.15) = 1.15 × bill
... 1.15 × $58.65 = $67.4475 ≈ $67.45
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Comment on percentages
The symbol % is a fancy (shorthand) way to write /100. The terminology "per cent" means "per hundred" or "divided by 100".
So, 15% = 15/100.
From your knowledge of place value and the meaning of decimal numbers, you know 15/100 (fifteen hundredths) = 0.15 (fifteen hundredths).
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Comment on 15% tip
10% = 10/100 = 1/10 of something can be computed by moving the decimal point one place left (dividing by 10).
5% of something is half of 10% of it.
15% is the sum of 10% and 5%.
Your bill is 58.65, so 10% of the bill is 5.865 ≈ 5.87. Half that is 2.9325 ≈ 2.93. The sum of 10% and 5% will be 5.87 +2.93 = 8.80, the amount that is 15% of the bill. Often, the numbers are such that this arithmetic can be done in your head.