<h3>Answer:</h3>
Markup on cost: 24%
Selling price: $39.70
<h3>Explanation:</h3>
A percent is a ratio with a base of 100. The word "percent" literally means "per 100", or "divided by 100". The symbol (%) is a shorthand symbol for /100 (divided by 100).
So, any percent is a ratio exressed using 100 as the denominator. An easy way to find it is to perform the division (find the ratio as a decimal), then multiply by 100%.
You want markup as a percentage of cost, so ...
... markup/cost × 100% = 7.80/31.90 × 100% ≈ 0.244514 × 100%
... ≈ 24.45% ≈ 24% . . . . (rounded)
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Of course, the selling price is the total of the cost price and the markup:
... selling price = cost price + markup
... = $31.90 + 7.80 = $39.70
