Final answer:
The selling price is 114.29% of the cost price when the marked price of a radio is 25% above the selling price and the cost price is 30% less than its marked price.
Step-by-step explanation:
The question asks us to determine what percentage the selling price is of the cost price when the selling price is 25% above the marked price and the cost price is 30% less than the marked price of a radio.
Let's assume the selling price is `$100`. According to the question, the marked price is 25% higher than the selling price, so the marked price would be $100 + 25% of $100 = $100 + $25 = `$125`.
Next, it is given that the cost price is 30% less than the marked price. So the cost price is $125 - 30% of $125 = $125 - $37.50 = `$87.50`.
Now we can find out what percentage the selling price is of the cost price. To do that, we divide the selling price by the cost price and then multiply by 100: (`$100` / `$87.50`) × 100 = `114.29%`.
Therefore, the selling price is `114.29%` of the cost price.