Points 'A' and 'B' are 70 km apart on a highway and two cars start at the same time. If they travel in the same direction, they meet in 7 hours, but if they travel towards each other they meet in one hour. Find the speed of the two cars (in km/hr).

Answer: Option B

Let the speed of the cars be S₁ and S₂
And S₁ - S₂ = $$\frac{70}{7}$$ = 10 . . . . . (i)
Also S₁ + S₂ = $$\frac{70}{1}$$ = 70 . . . . . (ii)
From equation (i) and (ii)
S₁ = $$\frac{10+70}{2}$$  = 40 km /hr
And S₂ = $$\frac{70-10}{2}$$  = 30 km / hr
∴ Required speeds are 40 km/hr and 30 km/hr