Answer:
- The equation is L = 2D+53
- After 33 days, the road length is 119 miles
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Explanation:
D = number of days
After 1 day, the crew adds on 2 miles. After 2 days, it's 2*2 = 4 miles. And so on. In general, the crew adds 2D miles of new road. For example, if D = 10 days go by, then the crew adds 2D = 2*10 = 20 miles of additional road.
This is on top of the 53 miles already done. Overall, we have 53+2D or 2D+53 miles of road. This is exactly what L is defined to be in the instructions.
Therefore, the equation is L = 2D+53
We can think of the 2 as the slope to represent how fast the road is growing (rate of change) and the 53 is the initial or starting value (y intercept).
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For the second part, we'll replace D with 33 to find out how much road we have after 33 days.
L = 2D+53
L = 2*33+53
L = 66+53
L = 119 miles is the length of the road at the 33 day mark.
