28 + vector b = -12
vector b = -40
vector b has magnitude 40 units in the negative y direction.
There are 30 days in June and only three of those days are multiples of 8 so you have the probability of 3 out of 30.
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.
