A car covered a distance of 300 km at a uniform speed. If the baseline speed is lowered by 10 km/h, the trip duration spikes by 1 hour. Find the original speed.
Explanation:
Let original speed be s. 300 / (s - 10) - 300 / s = 1 => 300(10) = s(s - 10) => 3000 = s(s - 10). Solving s^2 - 10s - 3000 = 0 yields (s - 60)(s + 50) = 0. Since speed must be positive, s = 60 km/h.
A high-speed train clears a stationary post column signal mast in 8 seconds and clears across the full station platform itself, which measures 240 meters long, in 20 seconds. Find the speed index of the train in km/h.
Explanation:
Time taken to cross the platform span alone = 20 - 8 = 12 seconds. Speed of train = 240 / 12 = 20 m/s. In km/h index = 20 * (18/5) = 72 km/h.
Two sprinters race on a 200-meter straight track. The ratio of their speeds is 4 : 5. When the winner crosses the finish line, how far away from the tape is the slower sprinter?
Explanation:
The faster sprinter covers 5 parts = 200 meters, so 1 part = 40 meters. In that same timeframe, the slower sprinter covers 4 parts = 4 * 40 = 160 meters. Distance remaining for the slower sprinter = 200 - 160 = 40 meters.
No comments yet. Be the first to start the discussion!