Correct Answers Submitted By : Nicole S . Sanborn , PE , Tidewater Civil and Surveying Donald A . Provencher , P . E ., Provencher Engineering , LLC Peter A . Tedder , P . E , Pennichuck Water Frank Koczalka , PE , RSP1 , VHB Nathan Miller , AICP , , So . NH Planning Commission Eric Steinhauser , P . E ., Sanborn , Head & Associates , Inc .
CRANIUM CHALLENGE
Rope Burning to measure time ?
You have three ropes that burn inconsistently . Each rope takes exactly one hour to burn from end to end . How can you measure 45 minutes using only these ropes and a lighter ?
Hint : you may burn one or multiple ropes from both ends .
Please send your answers to Thomas Selling via e-mail : thomasselling @ me . com Correct responses will be recognized in the future issues of the New Hampshire Civil Engineer
1 . |
Divide the bulbs into 3 groups of 3 , 3 , and 2 . |
2 . |
Weigh the two groups of 3 against each other . |
3 . |
If they balance , the heavier bulb is in the group of 2 . Weigh those
2 to find the heavier one .
|
4 . |
If one group of 3 is heavier , weigh any 2 bulbs from that group . If they balance , the third is heaviest ; if not , the heavier of the two is the answer . |
Correct Answers Submitted By : Nicole S . Sanborn , PE , Tidewater Civil and Surveying Donald A . Provencher , P . E ., Provencher Engineering , LLC Peter A . Tedder , P . E , Pennichuck Water Frank Koczalka , PE , RSP1 , VHB Nathan Miller , AICP , , So . NH Planning Commission Eric Steinhauser , P . E ., Sanborn , Head & Associates , Inc .