When going to the beach, Guilherme takes 2 hours on the road to go from his city to the beach and 3 hours to get back to his city. Knowing that Guilherme's car goes at 100 km/h when downhill, 80 km/h on plane surfaces and 50 km/h uphill, and that there are only 8 kilometers of road on plane surface, what is the distance in kilometers between the city and the beach?
Have you tried using the formula- \(d=st\) (or d=rt, whatever you want to call it); distance=speed*time.
For a round trip the uphill = downhill distances and the flat = 16 km
so U = D Total roundtrip distance = U + U + F U = uphill D = downhill
U/100 + U/50 + 16 / 80 = 5 hours
(U + 2U) / 100 = 4.8
U =160 and F = 16 and D = 160 ( roundtrip )
total ONE-WAY distance = ( 160+160+ 16 )/ 2 = 168 km