Palash drives from City A to B at 40 km per hour and returns over the same road at 30 km per hour and spends 8 hours away from home including a one hour stop for lunch. What is the distance (in km) between City A and City B?

A 100

B 120

C 140

D 180

Correct Answer: Option B

Let, distance from A to B = x km
ATQ,
x/40 + x/30 + 1 = 8
Or, 3x+4x/120 = 8-1
Or, 7x = 7 × 120
Or, x = 120
∴ distance = 120 km