Question

Two cars, X and Y, start from points 360 km apart and travel at constant speeds. If they move towards each other, they meet in 4 hours. If they move in the same direction, they meet in 12 hours. What is the speed of car X? (Assume X is the faster car).

• A. 60 km/h
• B. 75 km/h
• C. 45 km/h
• D. 90 km/h

Answer 1

Answer:

A. 60 km/h

Let speeds of cars X and Y be (x) and (y) km/h respectively, with (x > y).

Moving towards each other

$x + y = \frac{360}{4} = 90$

Moving in same direction

$x - y = \frac{360}{12} = 30$

Solve the system

Add both equations:
$(x+y) + (x-y) = 90 + 30$
$2x = 120 \Rightarrow x = 60$

Final Answer:

$\boxed{60 \text{ km/h}}$