Friday Riddle

nudgie

Remember NO googling or searching the Internet allowed and good luck!!!!!!!!!!!!!!

RIDDLE: Your assignment is to make a delivery from the depot to your base camp, 1600 miles away. The trip begins normally, but unfortunately, halfway to base camp, your supply truck breaks down. You have no way to call for help. Luckily, in addition to medical supplies, the truck is carrying a Desert Patrol Vehicle (DPV) and two barrels of fuel.

The DPV has a full 10 gallon tank, but to make room for the medical supplies, it can only carry one of the 45 gallon barrels at a time. While you can't transfer fuel between barrels, you can refill the tank from the barrels. Assume the DPV can get 12 miles per gallon, regardless of the load it carries.

How far can you go? Is it far enough to deliver the medical supplies and the DPV to your base camp?

Lilmiss82

I think I got it
1600 miles - (half way)= 800
10 gallons x 12(mpg)=120
one 45 gallon barrel will give you 540 miles (45x12=540)
Therefore DPV will not make it to base camp because there is only enough fuel to travel 660 miles (120+540) Making it 140 miles short of base camp.

SisterSledge

"regardless of the load"
So the DPV can tow the truck along to carry the second barrel of fuel and still get 12mpg...making enough gas for the trip, yes?

PGLGreg

Keep a full drum.
You want to get as far as you can, to within 660 miles of base camp, with a full DPV tank and a full 45 gallon drum, because then you can make it all the way to base. You transport one full drum 60 miles of the way toward base -- call that drum A, drop off drum A, drive back to where you had the breakdown, refill the DPV tank from the second drum, call that drum B, load up drum B on the DPV and drive back again to where you left drum A. Refill 5 gallons from drum B into the DPV tank. Now, you're 60 miles closer, the DPV tank has 10 gallons, drum A still has 45 gallons, drum B has 30 gallons.

You repeat this maneuver to get the full drum A 60 miles closer to base. Now drum B has 15 gallons.

One more repetition gets you and the full drum A another 60 miles, so you've made 180 miles of progress of the 800 miles to base, leaving just 620 miles to go. But now you've got 10 gallons in the DPV, you load up drum A with the 45 gallons, which is enough to go 660 miles, and head for base. You make it (with enough gas to spare to go another 40 miles).

--Greg