The weights of 40 students were recorded. if the 75th percentile of
their weights was 140 pounds, what is the total number of students
who weighed more than 140 pounds?
(1) 10 (3) 30
(2) 20 (4) 4

In the given question, there are numerous information's already provided. It is important to note then down first. With the help of those given information's the required answer can be easily reached.
Percentage of students that weighed 140 pounds = 75 percent
Then
Percentage of students that weighed more than 140 pounds = (100 - 75) percent
                                                                                                  = 25 percent
Total number of students that were weighed = 40 students
Total number of students that weighed more than 140 pounds = (25/100) * 40
                                                                                                    = (40/4) students
                                                                                                    = 10 students
So the number of students that weighed more than 140 pounds is 10. So the correct option in regards to the given question is option "1".

You need to do x2-x1,y2-y1 and divide it by 2 and you should get (1,-3)