Question

Tom sits in his car and Eli sits at his home, which is 33.0 km away from Tom. At the same moment, they begin listening to Pink Floyd's “Dark Side of the Moon,” which is 43.0 min in duration. At the same moment, Tom begins driving to Eli's house at constant speed. Suppose now that the speed of light is only 51.2 km/h. In this case, how much time remains until Tom's recording finishes?

I got the answer of .645 hr which is 38 min but the answer is 24.2 and I don't understand why that is the right answer. I used speed = d/t and plugged in 51.2 for speed, 33 for d and solved for t.

Answer 1

Tom's driving speed is v = 51.2 km/h.

The distance between Tom's car and Eli's house is s = 33 km.

If t time required by Tom to reach Eli's house then we know that s = vt.

So time taken by Tom is t = s/v = 33/51.2 = 0.6445 hour = 38.67 min.

The duration of the song is 43 min. So time remain after Tom's resch, before the song finish is (43 - 38.67) = 4.33 min. (Ans)

( Note that you have done this problem absolutely right. There is no other posdiblity. Either some information is missing or some information is given wrong question or ans is given wrong. Your solution with this information is absolutely right.)