You are travelling at a constant speed along a road. There are 5 sets of traffic lights along this road, and they all start their sequence at the same time as you pass the zero mile marker.

At what speed do you need to travel in order to remain at your constant speed?

traffic light 1 at 3 miles is red for 36 secs and green for 22 secs.
traffic light 2 at 4 miles is red for 28 secs and green for 40 secs.
traffic light 3 at 6 miles is red for 41 secs and green for 17 secs.
traffic light 4 at 7 miles is red for 62 secs and green for 15 secs.
traffic light 5 at 9 miles is red for 46 secs and green for 25 secs.

Note, the speed is an integer, above 25 and below 100MPH.

According to the note, the number is an integer "above 25 and below 100MPH".

In addition to this, the 47mph answer I have seen shows intelligent thought, but narrow thought at that.

There is never mentioned anything in the question that would preclude only answers which meet the 'green light' theorum.

Truth be told, any of the following should be acceptable:

26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99mph

But take note if you decide to experiment on such a premise. Be wary of other vehicles. That is all.

Posted by jeremy on 2005-03-02 04:43:15