Car M was driving on a highway at a constant speed of 50 miles per hou

If we treat Car M as a stationary object, Car N moved 5 miles in 15 minutes and its speed relative to M would be +20 mi/h. Since M is traveling at 50 mi/h, Car N is faster by 20 mi/h so it is traveling 70 mi/h. Therefore the answer is C.

We see that car N gains 2 - (-3) = 5 miles on car M in 20 - 5 = 15 minutes = 1/4 hour, so car N must be 5/(1/4) = 20 miles per hour faster than car M. Since car M is moving at 50 mph, car N must be moving at 70 mph.

Answer: B

Let the speed of car n is v miles /hr

a/c to question,

speed of car m is 50 miles/hr.

car n was 3 miles behind car m 20 minutes ago and 2 miles ahead of car m 5 minutes ago.

during 15 minutes , relative distance of car n becomes (3 + 2) = 5miles.

so, relative distance = relative velocity × time taken

or, 5 miles = velocity of car n with respect to car m × 15 min

or, 5miles = (v - 50miles/hr) × 15/60 hr

or, 5 = (v - 50) × 1/4

or, 20 = v - 50

or, v = 20 + 50 = 70 miles/hr

hence, speed of car n is 70 miles/hr

To solve this problem, we need to use the formula: distance = rate x time. Let's call the speed of Car N "r".

From the information given, we know that 20 minutes ago, Car M and Car N were 3 miles apart. In 20 minutes, Car M traveled (20/60) x 50 = 16.67 miles. So, Car N traveled (16.67 + 3) miles in 20 minutes.
Similarly, we know that 5 minutes ago, Car M and Car N were 2 miles apart. In 5 minutes, Car M traveled (5/60) x 50 = 4.17 miles. So, Car N traveled (4.17 - 2) miles in 5 minutes.

Now, we can set up two equations:
(16.67 + 3) = r x (1/3) (20 minutes is 1/3 of an hour) (4.17 - 2) = r x (1/12) (5 minutes is 1/12 of an hour)

Simplifying these equations, we get:
r = 70 miles per hour

Therefore, the speed of Car N was 70 miles per hour. The correct answer is (B).