Ursula's boss want's the commercial to be 30/100 * 30 = <<30/100*30=9>>9 seconds shorter.

After Ursula makes the desired changes, the ad is going to be 30 - 9 = <<30-9=21>>21 seconds long.

# Answer

21
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Ursula is working at a marketing firm. She created a 30-second long commercial. Her boss told her that this commercial is too long to air and told her to shorten the commercial by 30%. How long will this commercial be after Ursula makes the desired changes?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
21
Ursula is working at a marketing firm. She created a 30-second long commercial. Her boss told her that this commercial is too long to air and told her to shorten the commercial by 30%. How long will this commercial be after Ursula makes the desired changes?
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