Toni bought an old bike for 50$. she fixed it up and sold it for $80. what percent of the original value was toni’s sale price

For this case what you must do is the following rule of three:
 50 ---> 100
 80 > x
 We clear x:
 x = (80/50) * (100)
 x = 160%
 160-100 = 60%
 
 toni added 60% of the original value for his sale price

The first one is 2/3the second is 1/160the third is 4/125