Multiple choice

A man covers a distance of 81 km in 10 hours. He covers some distance on foot at a speed of 5 km/hr and some on a motorbike at a speed of 10 km/hr. What is the distance covered by the man on foot?

  1. 21 km

  2. 17 km

  3. 23 km

  4. 19 km

  5. 11 km
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let x be distance on foot. (x/5) + ((81-x)/10) = 10. Multiply by 10: 2x + 81 - x = 100. x = 19.

AI explanation

Using the formula for distance, let the time traveled on foot be x hours, making the time on the motorbike 10 minus x. The total distance is 5x plus 10(10 minus x), which equals 81 km. Solving 100 minus 5x equals 81 gives x equals 3.8 hours; multiplying this by 5 km/hr gives the distance covered on foot as 19 km.

Keep practicing — related questions