Jules is training for a marathon. She finds that for the first 5 km of her training run, she runs at a constant speed of x km/h. For the remaining 7 km of her training run, her speed reduces

Question

by 5 km/h. Write an algebraic expression for the total time Jules takes to run 12 km. Recall that s=t/d.

Answer 1

you have the formula, so plug and chug. t = d/s
time: 5/x + 7/(x-5) = (12x-25)/(x^2 - 5x)