You have to subtract both sides by 64 and you will get,
-50 = 5z. Then divide both sides by 5, and you get -10 = z.
11/4% = (11/4)/100 = 11/400 = 0.0275;
1/4 = 0.2500;
1/80 = 0.0125;
We observe that 0.0125 < 0.0275 and 0.0114 < 0.0275 and 0.2500 > 0.0275 and 0.12500 > 0.0275;
The answers are c. and d.
Owner would lose out on $100