Multiple choice

A car covers $300\ km$ at a constant speed. If its speed was $10\ kmph$ more, it would have taken $1\ h$ less to travel the same distance. Find the speed of the car.

  1. $60\ kmph$
  2. $50\ kmph$
  3. $40\ kmph$
  4. $75\ kmph$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let speed be v. 300/v - 300/(v+10) = 1. 300(v+10-v) = v(v+10). 3000 = v^2 + 10v. v^2 + 10v - 3000 = 0. (v+60)(v-50) = 0. Speed = 50 kmph.

AI explanation

Let the speed be x kmph and time be t hours, so x multiplied by t equals 300. The new condition is (x plus 10) multiplied by (t minus 1) equals 300. Substituting t equals 300/x yields x squared plus 10x minus 3000 equals 0, which solves to 50 kmph.

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