Correct Answer - Option 2 :
2.5 km/hr
Given:
Distance between two points A and B = 120 km
Speed of Ram = (y – 20) km/hr
Speed of Vishal = y km/hr
Concept used:
When two bodies move in the opposite directions, then
Relative Speed = Sum of Speeds
Speed = Distance/Time
Calculation:
Relative Speed = {y + (y - 20)}
Speed = Distance/Time
⇒ {y + (y -20)} = 120/4
⇒ 2y = 30 + 20
⇒ 2y = 50
⇒ Y = 25 km/hr
Speed of Vishal = 25 km/hr
Speed of Ram = 5 km/hr
⇒ 50% speed of Ram = 5 × 50%
⇒ 50% speed of Ram = 2.5 km/hr
∴ The 50% speed of Ram is 2.5 km/hr.