This is a quadratic so if you want to find the solutions, use the quadratic formula. Google quadratic formula and videos on it and how to use it will pop up.
(67 + 68 + 78 + x) / 4 = 70
(213 + x) / 4 = 70
213 + x = 70 * 4
213 + x = 280
x = 280 - 213
x = 67
(213 + x) / 4 = 79
213 + x = 79 * 4
213 + x = 316
x = 316 - 213
x = 103
lowest u can make is 67, highest u can make is 100
Reggie’s speed = distance/time
Reggie’s speed = 40.2 / 2.5
Reggie’s speed = 16.08 mi/hr
Craig’s speed = distance/time
Craig’s speed = 30.8 / 1.875
Craig’s speed = 16.43 mi/hr
Hence, answer is Craig
