Wednesday, August 22, 2007

Brain teaser.

I sit at work and work out my morning brain teaser to keep my analytical skills sharp and my mind right. But...Mikey's latest problem has got me in a bind. I gave him my answer and it was....wrong? How could that be? Where did I go wrong?

Try it...

Two marathon runners raced each other to see who was faster. Lucy ran three miles an hour up a hill and six miles an hour downhill. Olivia ran four miles an hour up and down the hill. The hill was 3 miles each way. Who won?

3 comments:

jay d said...

olivia. because she ran 4 miles an hour in total..up and down.

i think. maybe it's too late. shoot...why did i have to read this? i have a client in five hours.

JD said...

haha...ok well...that was my first answer, but i found out it was wrong.

first, i set up an inequality and isolated the time, which is the variable.

hence..

O = Olivia, L = Lisa and then solve according to the equation.

3L/H + 6L/H = 6 miles (total up and down)
so...

L = 3/2 mph = 90 min.

Now solve for Olivia using the same formula, just note she was at a constant 4 mi/hour...

Thus...

4O/H = 6 miles

O = 6/4 mph = 90 min.

They came in at the same time. It was a tie!

Yeah...took me a while to figure it out. I need to get on my game if I want to join Mensa, which is where this question came from.

jay d said...

fuck man.
i had a feeling there was more to it than it seemed.
ugh.