The Spotting Contest

During a recent plane and train spotting contest, five eager entrants were lined up ready to be tested on their spotting ability. 

They had each spotted a number of planes (26, 86, 123, 174, 250) and a number of trains (5, 42, 45, 98, 105). From the clues below, can you determine what colour shirt each was wearing, their position, their age (21, 23, 31, 36, 40) and the number of trains and planes spotted?

1. Bob spotted 44 less trains than planes. 

2. Tom was 36 years old. 

3. The person on the far right was 8 years younger than Bob, and spotted 174 planes. 

4. Josh was wearing a yellow shirt and spotted 37 trains fewer than Bob. 

5. The person who was wearing a green shirt, was 19 years younger than the person to his left. 

6. Steven spotted 105 trains and 250 planes.

7. The person in the center was 31 years old, was wearing a blue shirt and spotted 42 trains.

8. Doug, who was on the far left, spotted 26 planes, and spotted 72 trains more than planes. 

9. The person who was wearing a red shirt was 4 years older than Tom and was not next to the person wearing a blue shirt. 

10.The person who was next to the 31 year old, but not next to the person who spotted 26 planes, was wearing a orange shirt, and spotted 45 trains. 

Here are final STATS of the contest! 

Final Stats of The Spotting Contest

What was the contest?

Five participants having ages (21, 23, 31, 36, 40) had each spotted a number of planes (26, 86, 123, 174, 250) and a number of trains (5, 42, 45, 98, 105). 

Below are the clues given - 


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1. Bob spotted 44 less trains than planes. 

2. Tom was 36 years old. 

3. The person on the far right was 8 years younger than Bob, and spotted 174 planes. 

4. Josh was wearing a yellow shirt and spotted 37 trains fewer than Bob. 

5. The person who was wearing a green shirt, was 19 years younger than the person to his left. 

6. Steven spotted 105 trains and 250 planes. 

7. The person in the center was 31 years old, was wearing a blue shirt and spotted 42 trains. 

8. Doug, who was on the far left, spotted 26 planes, and spotted 72 trains more than planes. 

9. The person who was wearing a red shirt was 4 years older than Tom and was not next to the person wearing a blue shirt. 

10. The person who was next to the 31 year old, but not next to the person who spotted 26 planes, was wearing a orange shirt, and spotted 45 trains. 

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STEPS : 

Let's make at table like below and fill the data one by one.

 
STEP 1 : 

As per (3), the person on the far right that is at position 5 had spotted 174 planes & he must be 23 years old so that Bob aged 31 years (only pair of ages having 8 years difference.

 
STEP 2 : 

As per (7), the person at position 3 who is wearing blue shirt and is 31 year old. He has spotted 42 trains.

STEP 3 : 

For (5) to be true, the ages of those participants occupying consecutive positions must be 40 and 21 respectively. Only, positions lefts for (5) to be true are 1 & 2.

STEP 4 : 

And as per (8), the person at position 1 must be Dough who spotted 26 planes and spotted 72  trains more than planes i.e. 26 + 72 = 98 trains.

STEP 5 : 

As per (10), the person at position 4 must be wearing orange shirt and must have spotted 45 trains. His age must be 36 years (only number in ages list left).

STEP 6 :

As per (9) suggests, Tom must be 36 years old positioned at 4 and Dough must be the person wearing red shirt. With that, Josh in (4) must be wearing yellow shirt and positioned at no.5. 

STEP 7 : 

The hint (4), also suggests that Josh must had spotted 5 trains out of 42-5 possible spotted trains pair shared with Bob. Hence, the person at 2nd position must had spotted 105 trains (only number left in list of number of trains spotted).
 

STEP 8 : 

As per (3), the person having age 31 must be Bob. Hence, at no.2, Steven must be there. 

STEP 9 : 

As per (6), Steven have spotted 250 planes. As per (1), Bob must have spotted 42 + 44 = 86 planes. And the only number left as number of planes spotted for Tom is 123.

STEP 10 :

Final Stats look like as - 

Trip Around The Earth

Professor Fukano plans to circumnavigate the world in his new airplane. But the plane's fuel tank doesn't hold enough for the trip—in fact, it holds only enough for half the trip. But with the help of two identical support planes (which can refuel him in mid-air) piloted by his assistants Fugari and Orokana, the professor thinks he can make it in one trip. But since all three planes have the same problem of limited fuel, how can they work together to achieve the professor's goal without anyone running out of fuel?

1. The professor's plane must make a single continuous trip around the world without landing or turning around.

2. Each plane can travel exactly 1 degree of longitude in 1 minute for every kiloliter of fuel. Each can hold a maximum of 180 kiloliters of fuel.

3. Any plane can refuel any of the others in mid-air by meeting at the same point and instantly transferring any amount of fuel.

4. Fugari and Orokana's planes can turn around instantaneously without burning fuel.

5. Only one airport is available for any of the planes to land, take off, or refuel.

6. All three planes must survive the experiment, and none may run of fuel in mid-air.

'This' is how mission is completed!
  

For The Journey Around The Earth

First read T&Cs of the journey! 

Let's assume that the only airport mentioned is located at the top of the earth. 

Recollect all the data given.
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1. The professor's plane must make a single continuous trip around the world without landing or turning around.

2. Each plane can travel exactly 1 degree of longitude in 1 minute for every kiloliter of fuel. Each can hold a maximum of 180 kiloliters of fuel.

3. Any plane can refuel any of the others in mid-air by meeting at the same point and instantly transferring any amount of fuel.

4. Fugari and Orokana's planes can turn around instantaneously without burning fuel.

5. Only one airport is available for any of the planes to land, take off, or refuel.

6. All three planes must survive the experiment, and none may run of fuel in mid-air.

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As per (2), since each plane travel 1 degree of longitude in 1 minute for every kiloliter of fuel, means that plane need 360 minutes (6 hours) and 360 kiloliters of fuel. But remember plane can hold only 180 kiloliters of fuel.

Let's suppose that, all three planes takes off from airport exactly at 12:00 PM towards the WEST.

We will break this 6 hours journey into 8 parts where each plane travels 45 degree of longitude east or west using 45 kiloliters of fuel.  

START :

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PART 1 :

 Exactly at 12:45 PM, all will be at 45 degree angle with reference to the center of the earth.
At this point, each of them will use 45 kiloliters of fuel. Hence, each will have 135 kiloliters of fuel. Here, Orokana gives away 45 kiloliters to each of Fukano & Fugari. So she is left with the 45 kiloliters which she uses to go back to the starting point.

 
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PART 2 : 

In next 45 minutes, both Fukano and Fugari moves to 90 degree of longitude spending 45 kiloliters of fuel. Now,here both will have 135 kiloliters each in their fuel tank. Here, Fugari refuels Fukano's fuel tank with 45 kiloliters of fuel; leaving 90 kiloliters in own tank for the backward journey towards the starting point.

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PART 3 : 

Fukano travels further, while Fugari is in midway of the backward journey. Again, both spend 45 kiloliters of fuel.

 
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PART 4 :

Exactly at 3:00 PM, Fukano reaches at 180 degree while Fugari reaches back to the starting point. Till then, Orokana refuels her plane & takes off towards EAST. She has to take off as Fukano is left with only 90 kiloliters of fuel by which he could travel half of the rest of journey.

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PART 5 :

In next 45 minutes, Fukano's plane uses 45 kiloliters further while Orokana travels 1/3rd of Fukano's remaining journey in reverse direction so as to meet Fukano in midway. In process, her plane again uses 45 kiloliters of fuel with 135 kiloliters left.

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PART 6 :

At 04:30 PM, Orokana meets Fukano whose plane had no fuel left at the point & refuels his plane with 45 kiloliters of fuel. Remember Orokana's plane consumed 45 kiloliters more till she meets Fukano. Now, since both of them have left only 45 kiloliters in fuel tank, Fugari whose plane standing at airport is refueled at full 180 kiloliters takes of in the direction of EAST.

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PART 7 : 

At 05:15 PM, when fuel tank indicators of both Fukano & Orokana are pointing to 0, Fugari meets them & gives 45 (to Fukano) + 45 (to Orokana)  = 90 out of 135 (180 - 45 used since take off) . Now all are left with 45 kiloliters of fuel & 45 degrees of journey is left.

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PART 8 : 

And this is how, exactly at 06:00 PM all of them reaches back to the starting point safely.

But is this the most efficient way to make trip around the Earth? Certainly not! 

If plane was built with fuel tank of 360 + then the mission wouldn't have required any assistance. Just because of limited fuel tank, 45 + 45 + 90 + 90 + 90 + 90 + 45 + 45 = 270 Kiloliters of fuel burnt to assist Fukano's plane.