If we do not care about order, then a combination is an arrangement of r objects chosen from n distinct objects. It can often be seen written as:
or
Its factorial form is:
The probability that the monthly payment is more than $1000 will be found as follows;
The payment is normally distributed, thus the z-score will be given by:
Z-score=(x-Mean)/(SD)
Mean=$982
SD=$180
Thus;
Z-score=(1000-982)/180=0.1
The probability associated with a z-score of 0.1 is 0.5398
Thus the probability that the monthly payment is more than $1000 will be:
P(x<1000)=1-0.5398=0.4602=46.02%
I would say b because its 2 or more points on a graph otherwise its just a point