How to find the missing number 51- blank = 13

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

Question 1(multiple choice worth 1 points)(07.06 mc)a group of students must collect at least $150 to organize a science fair. they have already collected $30. which graph best represents all remaining amounts of money, in dollars, that thestudents should still collect to organize the science fair? -210 -180 -150 - 120 -90-60 -300306090 120 150 180 210-210 -180 -150 - 120 -90 -60 -30 0 30 60 90 120 150 180 210-210 -180-150 - 120 -90-60-300 30 60 90 120 150 180 210-210 -180 -150 - 120.90 -60 -30 0 30 60 90 120 150 180 210

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer