Multiple choice

Wan goes on a safari in Sahara. He walks half at 5 km/h. The next leg of the safari, which is 1/3rd the total distance, is covered on a cycle at 15 km/h. The last leg, which is over sand dunes, is done on a camel's back at an average speed of 9 km/h. He completes the safari in 19 hours. How much has he travelled?

  1. 100 km

  2. 125 km

  3. 135 km

  4. 150 km

  5. 140 km
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let total distance be D. Leg 1: D/2 at 5 km/h (time = D/10). Leg 2: D/3 at 15 km/h (time = D/45). Leg 3: D/6 at 9 km/h (time = D/54). Total time = D/10 + D/45 + D/54 = 19. (27D + 6D + 5D)/270 = 19 => 38D/270 = 19 => D/270 = 0.5 => D = 135.

AI explanation

Let the total distance be D kilometers, so the times for each leg are (1/2 D) / 5, (1/3 D) / 15, and (1/6 D) / 9. Adding these times gives the equation (3D + 2D + 5D) / 90 = 19 hours. Solving for D, we get 10D / 90 = 19, which means D / 9 = 19, making the total distance travelled 135 km.

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