Making 1 necklace takes her 0.5 hours, so making x necklaces, will take her 0.5x hours.
Making 1 bracelet takes her 1 hour, so making y bracelets, will take her 1*y=y hours.
So in total, she needs to work for 0.5x + y hours.
Since she has fewer than 20 hours, 0.5x + y must be smaller that 20.
Thus, we have 0.5x + y<20
Answer:0.5x + y<20