Answer:
The origin is (0, 0) so let's say we have (0, 5) we find that this point is 5 units away from the origin. We find that by subtracting the origin's y coordinate from our (0, 5) point's y coordinate. This method can be used for the x-axis too.
Total number of ways to make a pair:
The first player can be any one of 7 . For each of those . . .
The opponent can be any one of the remaining 6 .
Total ways to make a pair = 7 x 6 = 42 ways .
BUT ... every pair can be made in two ways ... A vs B or B vs A .
So 42 'ways' make only (42/2) = 21 different pairs.
If every pair plays 2 matches, then (21 x 2) = <em><u>42 total matches</u></em> will be played.
Now, is that an elegant solution or what !
Since 120 students gained less than 70, and 70 is the upper quartile, 120 people are in the 75% of all the students so we need to find the total number of students.
we need to multiply 0.75 (75%) by something to get 120. which is 160 (the total number of all students).
and since 48 is the median score, find 50% of 160 which is 80!
hope this helps :)