Abhay takes 2 hours more than Sameer to cover 30 km. If Abhay doubles his speed, he would take 1 hour less than Sameer. What is Abhay's speed (km/h)?

Translate the time statements into equations using Time = Distance / Speed.

Step-by-step calculation
Let Abhay’s speed = a and Sameer’s speed = s (km/h).
30 / a = 30 / s + 2   …(1)30 / (2a) = 30 / s − 1   …(2)Subtract (2) from (1):
30/a − 30/(2a) = (30/s + 2) − (30/s − 1)15/a = 3a = 5 km/h

Verification
Abhay time = 30 / 5 = 6 hFrom (1): 6 = 30/s + 2 ⇒ 30/s = 4 ⇒ s = 7.5 km/hIf Abhay doubles speed to 10 km/h: time = 30/10 = 3 h, which is 1 h less than Sameer’s 4 h (matches)

Common pitfalls
Be careful with “2 hours more” vs “1 hour less” and ensure you attach them to the correct person’s time.

Final Answer
5 km/h