Answer:
52.34 miles per hour
Step-by-step explanation:
Let x represents the distance covered by car and y represents the distance covered by truck,
Also, suppose l represents the distance between them,
∵ car is travelling in east direction while truck is travelling in north direction,
So, by the Pythagoras theorem,
Differentiating with respect to t ( time ),
,
Now, the speed of car is 33 mi/hr and speed of truck is 42 mi/hr,
i.e
,
Distance = speed × time,
So, y = 42 × 2 = 84 miles,
x = 33 × 3 = 99 miles ( ∵ car travelled 3 hours till 1 PM while truck travelled 2 hours till 1 PM)
From equation (1),
From equation (2),
Hence, the distance between them is increasing by 52.34 miles per hour.