Answer:
18.333333333333333333333333
For this you would do

Because 60% is the same as 0.60. And solving a problem like this is the opposite of finding a percent of a number. When you solve this you get 80. So there are 80 students in total.
1: (-1,-1) is (x, y) to see if it is a solution, you would just plug in x and y and see if the equation is true.
-4 (-1) + 2(-1) = 2
4 + -2 = 2
2 = 2 CORRECT
So... plug in x and y in the second equation to Make sure it works for that one too.
-1 + -1 = -2
-2 = -2 CORRECT
So, yes. (-1,-1) is a solution to both equations.
The triangle inequality tells you the third side will be between the difference and sum of the other two sides.
5 < third side < 21
25 feet above sea level means she travelled 25 feet to the surface of the sea. She would have to descend (37-25=12) 12 more feet to achieve 37 total feet of travel, so she descended 12 feet below sea level.