To qualify for the Indianapolis 500 race, a car must average 350 km/hr for four laps. Of a driver averages 285 km/hr for the first two laps, what average speed must be achieved for the final two laps in order to qualify?

Answer 1

350=.5*285 +.5*V
V= 700-285= you do it.

Answer 2

Average = Sum of quantities/Total quantities
350 = (2X + (285 * 2))/4
350 * 4 = 2X + 570
1400 - 570 = 2X
X = 830/2
X = 415 m/s