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Explanation:
She has already ran 8 miles, so she has 26-8 = 18 miles left to go.
She runs at a pace of 7.5 mph, which means she has 18/(7.5) = 2.4 hours left to go.
I used the equation distance = rate*time, and solved for time to get time = distance/rate.
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Another approach:
Here's how you can use algebra.
x = time she has left in hours
7.5x = distance covered in those x hours
7.5x+8 = total distance
7.5x+8 = 26
7.5x = 26-8
7.5x = 18
x = 18/(7.5)
x = 2.4