M7MBA wrote:Pat traveled a distance of 240 miles in x hours. For a part of the journey, he was traveling at a constant speed of 40 miles per hour whereas for the remaining part of the journey he was traveling at a constant speed of z miles per hour. How long was he traveling at z miles per hour?
(1) Average speed for the journey is 48 miles per hour.
(2) z > 48 miles per hour
The OA is E.
Aren't sufficient both statements together? Could someone explain this question? Thanks.
Say Pat traveled a miles at a constant speed of 40 miles per hour, thus, he traveled (240 - a) miles at a constant speed of z miles per hour
=> Time taken to travel a miles + Time taken to travel a miles = x hours
a/40 + (240 - a)/z = x
We need to find out the value of (240 - a)/z.
Let's see each statement one by one,
(1) Average speed for the journey is 48 miles per hour.
=> x = 240/48 = 5
=> a/40 + (240 - a)/z = 5
But we cannot get the value of (240 - a)/z. Insufficient.
(2) z > 48 miles per hour
With this information, we cannot get the value of (240 - a)/z. Insufficient.
(1) and (2) together
Even combining both the statements cannot help as we cannot get the value of (240 - a)/z. Insufficient.
The information "z > 48 miles per hour" is redundant; since the average speed is 48 miles per hour and one of the two speeds is less than 48 (= 40), the other speed must be greater than 48.
The correct answer:
E
Hope this helps!
-Jay
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