Multiple choice

A cargo vessel sailed a fixed distance over the ocean at a constant speed. If its speed had been 9 km/h faster, it would have taken 2 hours less to complete the journey. If its speed had been 9 km/h slower, the journey would have taken 4 hours more. What was the original speed, in km/h, of the vessel?

  1. 18

  2. 27

  3. 36

  4. 44

  5. a
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the original speed and time be v and t. The distance equations are (v + 9)(t - 2) = vt and (v - 9)(t + 4) = vt. These give 9t = 2v + 18 and 9t = 4v - 36, so v = 27 km/h.

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