
Velocity of approach,
$v = \sqrt{60^2 + 40^2}$
$v = 72.11 \, \text{ mi/hr}$ answer
At 12:30 PM
Distance traveled by car from E
= 40(30/60)
= 20 miles
Distance traveled by car from F
= 60 [(30 - 10)/60]
= 20 miles
The cars may/will collide at this time. ← answer