A florist buys roses in bulk to be sold at a retail price of $30 per

first of all we have to get the earrings if all roses would have been sold, that is: 288× 30=8640$

we know that 12 of roses have been sold at half of the retail price. 12×15=180$

And we know 24 of roses have not been sold .24×30=720$
720+180=900$

The amount of money which has been paid for buying all roses is: 24×288= 6912

So: 8640-6912=1728$, the profit required.
900/1728=~52
Option D

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Retail Price $30 per dozen (= $3 per rose), earning a 25 percent profit( actual price of each rose is $2.4). We have 288 roses in total.
Let's calculate the total profit: 288*3-288*2.4=864-691.2=172.8

So, we need also actual profit( Because, 24 roses were not sold due to wilting and 12 roses were sold at half of the retail price.)
288-24=264 --> 264-12=252 -->252*3=756
12*1.5=18
756+18=774(actual income)
774-691.2(actual price of 288 roses)=82.8 (actual profit)

And we can find the 'total lose' as a result of the roses that were not sold and those that were sold for half price:

TOTAL PROFIT -ACTUAL PROFIT=172.8-82.8=90

The question is asking that how many percent of the total profit was lost?
So, we got everything now:
172-->100%
90-->x%
x=90*100/172=52.08%
The answer choice is D (52% )

Guys, one question... I understood this question on the basis of standard financial ratios: profit margin is calculated using sales and not COGS. With this in mind, if the cost is 24, as mentioned above, the profit would be 6 dollars, so actually the profit margin he would earn would be 6/30=20% instead of 25%. Solving the math to match 25% of profit, under my interpretation, the answer would be very close to question C. Is GMAT likely to ask a question with possibility of different interpretations, such as this one?