Speed is distance over time. Your desired speed has the man traveling D distance in some time, say T. However, the man was attacked by a crazy Irishman as he neared the destination. As a result, his actual time was S, which was 120 seconds off. If he had been on time, he would have taken S - 120 (which is T) seconds to get there.
So your speed would be D / (S - 120) ft /s.
PS: No one uses Imperial anymore. Go metric, silly Yank/Brit
God, I'd forgotten how they word those types of questions so that they are hard to wrap your brain around. I suppose it's designed to help you think "outside the box" eh?
One of us has misread the question. 249 may be the number of odd numbers between 0 and 500, but he needs numbers that have all odd digits.
Fairly simple, I think. I'm pretty good at messing simple stuff up, though. 1,3,5,7,9--5. Every other set of 10s will be odd, plus the original 1,3,5,7,9. So for every 10 sets of 10, five will contain odds, and we'll add in 5 for the original 1,3,5,7,9.
Now the hundreds. For xx, odds are possible. 1xx, odds are possible. 2xx, no. 3xx, yes. 4xx, no.
So 3 sets of 100 we'll look at. 5*5*3+5= 80. Five for 5 odd numbers; 5 for 5 out of every ten sets of ten beginning with an odd number, 3 for 3 possible fields of 100's to work from, and 5 for the extra 1,3,5,7,9 that are only possible in the first set of 100. I don't see any mistakes, but that doesn't mean they aren't there.
Don't be surprised if this is the overcomplicated way of doing it. It probably is.
edit: ah, but someone posted an answer before me. Dembonez, isn't 0 even?
Wow, this makes me glad that I'm out of high school. I sucked at math.
You never truly escape Math... But you don't need to use complex formulae to balance the old checkbook. And most things these days are full of computers you don't even need most math skills. My bimmer tells me how full the gas tank is and computes the gas milage and will tell me how far I can drive on the gas left in the tank.
Computers are making it so people rely less and less on the basics.