A race car driver must average 200 km/hr for four laps to qualify for a race. because of engine trouble, the car averages only 170 km/hr over the first two laps. what average speed must be maintained for the last two laps?

Question

Physics

Carson Haney

12 September, 04:25

A race car driver must average 200 km/hr for four laps to qualify for a race. because of engine trouble, the car averages only 170 km/hr over the first two laps. what average speed must be maintained for the last two laps?

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Answers (1)

Know the Answer?

Keely Matthews · Answer 1

To know the average, let us assign values for each of the four laps as x, y, v and w. The average of the first two is 170. So, we can determine the sum of x and y:

(x+y) / 2 = 170

x = y = 340

Next, we have to find the value for (v+w):

(x+y+v+w) / 4 = 200

[340 + (v+w) ]/4 = 200

v+w = 460

So, we can now determine the average of the last two laps:

Average = (v+w) / 2 = 460/2 = 230 km/h