In the qualifying rounds for a race , Rusty and Date drive theif cars around a 6,000 - foot oval track . Rusty and Dale each drive 8 laps in the qualifying rounds in lanes of identical length .
On the second day of the qualifying rounds , Rusty averages 180 seconds per lap until he begings the last lap . He then goes into a lower gear . He averages 190 seconds per lap for this qualifying round . How many seconds does Rusty take to drive the final lap ?

Options

A. 155
B. 160
C. 260
D. 200

Answer

To solve the problem, we need to find out how many seconds Rusty takes to drive the final lap of the race. Here’s a step-by-step breakdown of the solution:

### Step 1: Calculate the total time taken for the first 7 laps
Rusty drives the first 7 laps at an average of 180 seconds per lap.

\[ \text{Total time for 7 laps} = 7 \text{ laps} \times 180 \text{ seconds/lap} = 1260 \text{ seconds} \]

### Step 2: Calculate the total time taken for all 8 laps
Rusty averages 190 seconds per lap for all 8 laps.

\[ \text{Total time for 8 laps} = 8 \text{ laps} \times 190 \text{ seconds/lap} = 1520 \text{ seconds} \]

### Step 3: Find the time taken for the final lap
To find the time taken for the final (8th) lap, we subtract the total time for the first 7 laps from the total time for all 8 laps.

\[ \text{Time for final lap} = \text{Total time for 8 laps} - \text{Total time for 7 laps} \]

\[ \text{Time for final lap} = 1520 \text{ seconds} - 1260 \text{ seconds} = 260 \text{ seconds} \]

### Conclusion
Rusty takes **260 seconds** to drive the final lap.

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