Answer:
They should increase their price by $28.
Step-by-step explanation:
First find out what 35% of 80 is. Do so by multiplying 80 by 35% in its decimal form - .35.
80*.35=28.
This means that they have to increase their price by at least 28 dollars to make a profit.
The new price of the instrument should be $108 - $80 increased by 35%.
Hope this helps :)