Brodie and Ryan are driving directly towards each other. Brodie is driving at a constant speed of $50 \mathrm{~km} / \mathrm{h}$. Ryan is driving at a constant speed of $40 \mathrm{~km} / \mathrm{h}$. If they are $120 \mathrm{~km}$ apart, how long will it take before they meet?
(A) $1 \mathrm{~h} 12 \mathrm{~min}$
(B) 1 h $25 \min$ (C) 1 h 15 min
(D) 1 h 33 min
(E) $1 \mathrm{~h} 20 \mathrm{~min}$
When Brodie and Ryan are driving directly towards each other at constant speeds of $50 \mathrm{~km} / \mathrm{h}$ and $40 \mathrm{~km} / \mathrm{h}$ respectively, then the distance between them is decreasing at a rate of $50+40=90 \mathrm{~km} / \mathrm{h}$.

If Brodie and Ryan are $120 \mathrm{~km}$ apart and the distance between them is decreasing at $90 \mathrm{~km} / \mathrm{h}$, then they will meet after $\frac{120}{90} \mathrm{~h}$ or $\frac{4}{3} \mathrm{~h}$ or $1 \frac{1}{3} \mathrm{~h}$.

Since $\frac{1}{3}$ of an hour is $\frac{1}{3} \times 60=20$ minutes, then it will take Brodie and Ryan $1 \mathrm{~h} 20 \mathrm{~min}$ to meet.

ANSWER: (E)