Scaling running distance with constant pace: In a race scenario, Ravi covers 5 km in 20 minutes at a steady pace. Assuming he keeps the same speed, how much distance (in kilometers) will he cover in 100 minutes?

Introduction / Context:
This is a direct-speed scaling question. If a runner maintains constant speed, distance is proportional to time. The unitary method converts a known time–distance pair to a longer duration at the same speed.

Given Data / Assumptions:

• Distance D1 = 5 km
• Time t1 = 20 min
• Desired time t2 = 100 min
• Speed remains constant across the entire period.

Concept / Approach:
Speed v = distance / time. With constant v, distance scales linearly with time: D2 = v * t2 = (D1 / t1) * t2. Convert minutes consistently or keep a ratio to avoid unit errors.

Step-by-Step Solution:
Speed = 5 / 20 = 0.25 km/minDistance in 100 min = 0.25 * 100 = 25 km

Verification / Alternative check:
Proportion approach: 100 min is 5 times 20 min. Therefore, distance is 5 times 5 km = 25 km. Same result as above.

Why Other Options Are Wrong:
40 km and 35 km overstate the pace; 26 km is an off-by-one distractor; 30 km assumes a higher speed than given.

Common Pitfalls:
Mixing minutes and hours incorrectly. Since both times are in minutes, a direct ratio avoids conversion mistakes.

Final Answer:
25 km