Question 251896
A 150% increase is always possible.  Note that a 150% increase is the same as multiplying by 2.5, not 1.5.  A 150% increase from 100 --> 250, not 150.  Likewise, 4 times faster is 5 times as fast, a distinction that is often lost on writers of textbooks.
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If you're dealing with objects, a 150% decrease might not be possible.  For example, if you start with 10 apples, you can't have a 150% decrese in the number because you get -5 apples.  It's possible in theoretical things, but can be contradictory in objects, and lead to nonsensical statements.