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An auto race consists of 15 laps. Jon Kimm completes the first 3 laps at an average speed of 195 mph, and the remaining laps at an average speed of 205 miles per hour. Let d represent the length of one lap. Choose the time in terms of d that it takes the driver to complete the race.

User Elham Gdz
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Final answer:

The time it takes for Jon Kimm to complete the race is approximately 203.697 seconds.

Step-by-step explanation:

To calculate the time it takes for Jon Kimm to complete the race, we need to find the total distance he travels and divide it by his average speed.

The first 3 laps are completed at 195 mph, so the distance covered in those laps is 3d (since d represents the length of one lap).

The remaining laps are completed at 205 mph, so the distance covered in those laps is 12d (since there are 15 laps in total and 3 have already been completed).

The total distance covered is 3d + 12d = 15d.

To find the time, we divide the total distance by the average speed.

The average speed is the total distance divided by the total time. Since we don't have the total time, we'll keep it as a variable t.

Therefore, the equation becomes:

15d/t = (3d/195) + (12d/205)

To solve for t, we can cross multiply:

15d = (3d/195) * t + (12d/205) * t

15dt = 3dt/195 + 12dt/205

Applying the same denominator, we get:

15dt = (205 * 3dt + 195 * 12dt) / (195 * 205)

Simplifying further:

15dt = (615dt + 2340dt) / 39975

Combining like terms:

15dt = 2955dt / 39975

Dividing both sides by dt:

15 = 2955 / 39975

Multiplying both sides by dt:

dt = (15 * 39975) / 2955

Finally, simplifying the expression gives us:

dt = 203.697 seconds

User Savas Vedova
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