my answer is 1/3.

Let the total distance be 1. The distance covered on 30mph= x; so the distance covered on 60 will be 1-x

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X (1-x)

Equating times,

x/30 + 1-x/60 = 1/50;

Solving we get, X= 1/5.= so distance covered at 30mph=1/5 and distance covered at 60mph=4/5

Time calculation,

Time taken to cover 1/5 jounery at 30mph= 1/150.

Total time taken for the entire jouney= 1/50.

Fraction of the time.

1/150/1/50 = 1/3 (option B).

Please correct me if wrong.

Bunuel wrote:

Myra drove at an average speed of 30 miles per hour for some time and then at an average speed of 60 miles/hr for the rest of the journey. If she made no stops during the trip and her average speed for the entire journey was 50 miles per hour, for what fraction of the total time did she drive at 30 miles/hour?

(A) 1/5

(B) 1/3

(C) 2/5

(D) 2/3

(E) 3/5

Kudos for a correct solution.

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Kudos to you, for helping me with some KUDOS.