At time $t = 0$, cars X and Y are placed as shown. Both cars move in the same direction. X is $50\ \text{m}$ behind Y and travels at a constant speed of $30\ \text{m s}^{-1}$. Y travels at a constant speed of $20\ \text{m s}^{-1}$. Find the value of $t$ when X is level with Y.
- A$1.0\ \text{s}$
- B$1.7\ \text{s}$
- C$2.5\ \text{s}$
- D$5.0\ \text{s}$