Multiple choice

A man walks a certain distance in a certain scheduled time. If he had walked 4 km/hr faster, then he would have taken 1 hr less than the scheduled time. If he had walked 3 km/hr slower, then he would have taken 1 hr more than the scheduled time. The distance (in km) walked by the man is

  1. 145 km

  2. 155 km

  3. 168 km

  4. 147 km

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let distance be D and speed be S. D/S - D/(S+4) = 1 and D/(S-3) - D/S = 1. Solving these equations: D = S(S+4)/4 and D = S(S-3)/3. S^2+4S = 4D/S * S? No, equate: S(S+4)/4 = S(S-3)/3. 3S+12 = 4S-12. S = 24. D = 24(28)/4 = 168.

AI explanation

Let the original speed be v km/hr and the scheduled time be t hours. Using the Distance formula, we write vt = (v+4)(t-1) and vt = (v-3)(t+1). Simplifying these equations yields 4t - v = 4 and 3t - v = -3. Solving this system gives v = 28 km/hr and t = 6 hours. The distance walked by the man is 28 multiplied by 6, which equals 168 km.

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