Brain Teasers
Rattlesnake Jake
It's time to paint the Big Barn, and Paul has enlisted the help of "Rattlesnake" Jake, his rancher neighbor from across the Snake River. Jake is feelin' a mite achy, having spent the previous day bustin' some broncs, so it takes him six hours to paint one wall. Paul plans to spend some time with Miss Rosy Boa later in the afternoon, so he gets his wall done in three hours. Assuming all the walls are the same size, how much time would it take Paul and Jake to complete another wall while working together at their previous pace?
Answer
2 hours.Breaking down the job on an hourly basis, Paul can finish 1/3 of the job in an hour, while Jake completes 1/6 of the wall in the same hour. Working together, they will complete 1/3 plus 1/6 (or 1/2) of the wall in one hour, and finish the job in two.
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Comments
Jan 20, 2003
that was a good 1
pretty good!
Imagine the wall is 6 square metres. Jake paints a 1 sq m per hour, Paul paints at 2 sq m per hour. Together they paint at 3 sq m per hour. It takes 2 hours (no fractions needed)!
By the way K2W2man, I enjoye d the puzzle!
Easier than looking at how much wall each paints in some interval of time, look at the proportion of the wall that each paints.
Paul paints 6/(3+6) = 2/3 of the wall and it takes 2/3 * 3 = 2 hours.
The 6/(3+6) represents the portion of the wall that Jake doesn't paint, which is equal to the portion that Paul paints.
Paul paints 6/(3+6) = 2/3 of the wall and it takes 2/3 * 3 = 2 hours.
The 6/(3+6) represents the portion of the wall that Jake doesn't paint, which is equal to the portion that Paul paints.
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