Puzze - How far?

[Lisa]

Jack and Jill took turns driving on a round trip using the same route both ways. Jack drove the first 40 miles and then Jill drove the rest of the way.
Jack started to drive on the return trip and then Jill drove the last 50 miles. Which of the two drove more miles and how many more did the person drive?

[Smitty]

Got it, but I won't post it until other people have a chance.

[Edwin]

Hmm.. they each drove 90 miles, and neither person did more driving than the other.

It is a round trip, therefore the distance between destinations are equal.

Jack's 40 miles + Jill's A miles = Jack's B miles + Jill's 50 miles

Rearranging,

A + B = 40 miles + 50 miles

Solving, A = 50 and B = 40

Is that right, Lisa?

[Lisa]

nope, keep trying. you're counting both trips as one with your equasion, the 40miles is during the first trip and the 50 miles is during the return (second) trip.

[alan]

nah...i think it's more like Jill drove 20 miles more. It's pretty simple, just put a number into the equation and u'll get the ans

[Lisa]

Alan is right. with the total amount of driving added up Jill does 20 miles more regardless of the distance (the distance has to be more then 50 miles).

[Smitty]

I was wrong. :)