Regina had 30 m of ribbon. She gave 2.7 m of the ribbon to each of her 4 friends and used the rest to decorate some presents for a party. 70 cm of ribbon were needed to decorate each presents. Find the most number of presents she could decorate. The answer is not 42
Regina gave away a total of 2.7 m/ribbon * 4 friends = <<2.7*4=10.8>>10.8 m of ribbon.
She had 30 m – 10.8 m = <<30-10.8=19.2>>19.2 m of ribbon left to decorate the presents.
Every present required 70 cm/ribbon * 1 m/100 cm = <<70/100=0.7>>0.7 m of ribbon.
Therefore, Regina could decorate 19.2 m / 0.7 m/present = <<19.2/0.7=27.43>>27.43 presents.
Since she cannot have a fraction of a present, the most number of presents she could decorate is 27. Answer: \boxed{27}.