Answer:
move the constant to the right hand of the side and change the sign 
2x>-0.5-5-5
calculate the difference 
2x>-6
divide both sides of the inequality by 2
x>-3
solution X>-3
 
        
             
        
        
        
160cm3 
2/5 - 1/4 = 8/20 - 5/20 = 3/20
(3/20)t = 24
t = 160 
        
             
        
        
        
C. Buying it a percent discount without sales tax.
Because of not having to pay $10, so it is awesome.