



 
Hi Maria. The main formula is distance = speed x time. The distance is the same for Kim and Julie (150 km). Assign variables (letters) to the unknown quantities, then try to reduce the number of unknowns: Let s = Kim's speed. So: That's four unknown quantities  can we reduce this with more information? yes. We know that Kim's speed is Julie's speed minus 20: We also know that Kim spend an extra hour and a quarter driving, so t = T + 5/4 That's two unknowns. Can we get down to one? yes. Because if 150 = ST, then T = 150/S, so (S  20) ( 150/S + 5/4) = 150 Now you have one equation with one unknown in it. Can you solve it from here? Stephen La Rocque.>  


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