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# Speed Distance Time for Dummies

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Hi all,

I hope this thread still gets some attention as I'm having a brain-fart with this one for some reason, I can work it out long-windedly, but not at the speed I'd need to be able to...

At 45 mph, how long does it take to travel 162 miles?

What's the most rapid method to work this one out, in your head?

I'd also like to thank everyone who posted here, especially you, Q_M! I have my CBAT on the 4th of Feb and all these helpful comments have been invaluable to me. I've been smashing through tons of SDT questions with help from this thread, but I'm far from comfortable with them yet.

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Hello,

For starters those are quiet tricky numbers that don't go into each other that well, so I don't know if they'll be that tricky but it's best to be prepared.

First of all you know that in 60mins you travel 45miles.
Therefore it takes 3hrs to travel 135 with 27miles left.
So now we want to know how long it takes to travel 27miles.
Easiest way to do this I find is to find a number that goes into both 45 and 27. (9)
You can work out (45/9=5) that you travel 9miles in 5minutes.
To find out how long it takes to travel 27miles....27/9=3 and then 3x5minutes= 15 minutes
So the answer is 2hrs 15minutes.

I'm studying these questions for an aptitude test coming up and I've found that if you can learn patterns of what numbers go into an hour it really helps!! I.e. 2,30's. 3,20's. 4,15's. 5,12's.
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I would hate to see you guys at 80 feet off the deck in the Welsh Valleys caning it at 300 knots. LOL.
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Would greatly appreciate a second pair of eyes on these ones:

at 75 mph how far do you travel in 1 hour and 8 minutes

at 192 mph how long does it take to travel 176 minutes

at 85 mph how long does it take to travel 204 miles

have been kicking myself for a few days over them
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Great Thread, I have been hammering my SDT work in preparation for my RN FATS and I'm now starting work on fuel burn calculation.

I'm a little stuck with these two question:

You travel 88 miles. How much fuel will you need if you burn 18 kgs per minute, and are travelling at 132 mph?

You travel 156 NM. How much fuel will you need if you burn 25 kgs per hour, and are travelling at 195 kts?

I understand the base 60 relationship very well but I can't seem to see the patterns in these question.
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(Original post by Trihard)
Great Thread, I have been hammering my SDT work in preparation for my RN FATS and I'm now starting work on fuel burn calculation.

I'm a little stuck with these two question:

You travel 88 miles. How much fuel will you need if you burn 18 kgs per minute, and are travelling at 132 mph?

You travel 156 NM. How much fuel will you need if you burn 25 kgs per hour, and are travelling at 195 kts?

I understand the base 60 relationship very well but I can't seem to see the patterns in these question.

Q1. We notice that conveniently 44 is a factor of both 132 and of 88. Ergo it takes us 2/3 of an hour ie 40 minutes to fly 88 miles. At 18 kgs per minute we burn 40 x 18 = 720 kgs of fuel. Tally ho chaps.
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Q.2 Hint: we notice immediately that 156 and 195 are both divisible by 13.
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(Original post by Old_Simon)
Q.2 Hint: we notice immediately that 156 and 195 are both divisible by 13.
You travel 392 miles. How much fuel will you need if you burn 135 kgs per hour, and are travelling at 210 mph?

If you have time id really appreciate any help on these and the SDT ones I posted yesterday? no worries if not though Got my aptitude tests at Cranwell next week
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(Original post by Redders13)
You travel 392 miles. How much fuel will you need if you burn 135 kgs per hour, and are travelling at 210 mph?

If you have time id really appreciate any help on these and the SDT ones I posted yesterday? no worries if not though Got my aptitude tests at Cranwell next week
Lol. You have to do this for real, upside down, pulling 6g, and doing 500 knots in an aircraft that cost the tax payer tens of millions of pounds. Ok the Q above ( these need to be done in your head in seconds if you ever want to sit in a military aircraft)

In the first hour we do 210 miles. We subtract that from 392 so we have 182 miles to run. What is 182/210? We notice immediately that both 182 and 210 are divisible by 14 conveniently giving us 13/15. 1/15 of one hour takes 4 minutes. We burn fuel at 135 kgs an hour and we notice immediately by inspection 135 is divisible by 15 giving us 9.
13 x 9 = 117 kgs. So in total we burn 210 + 117 kgs of fuel.
Simples.
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(Original post by Redders13)
Would greatly appreciate a second pair of eyes on these ones:

at 75 mph how far do you travel in 1 hour and 8 minutes

at 192 mph how long does it take to travel 176 minutes

at 85 mph how long does it take to travel 204 miles

have been kicking myself for a few days over them
Ok. Q1. We notice 8 minutes is divisible by 4. 8 mins is therefore 2/15 of one hour. Conveniently (as is normal in this type of question) 15 divides into 75 very neatly giving us a rate of 5 miles in 4 minutes. So in 2/15 of an hour we do another 10 miles. 75 + 10 = 85 miles covered.
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(Original post by Old_Simon)
Ok. Q1. We notice 8 minutes is divisible by 4. 8 mins is therefore 2/15 of one hour. Conveniently (as is normal in this type of question) 15 divides into 75 very neatly giving us a rate of 5 miles in 4 minutes. So in 2/15 of an hour we do another 10 miles. 75 + 10 = 85 miles covered.
thank you very much, it is proving very hard to get my head round these, esp the fuel consumption, when i did a history degree lol. I will keep practicing, since posting the fuel consumption questions I have been working on these on that SDT website and just got all 10 right, albeit with a pen and paper! so I think it might be a case of slowly but surely thank you again!!
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(Original post by Redders13)
thank you very much, it is proving very hard to get my head round these, esp the fuel consumption, when i did a history degree lol. I will keep practicing, since posting the fuel consumption questions I have been working on these on that SDT website and just got all 10 right, albeit with a pen and paper! so I think it might be a case of slowly but surely thank you again!!
I noticed all these questions have one thing in common. They always divide out neatly and you get something over 15 quite often. Also learning your times tables from 11 to 19 will really help eg what are 13 x 14 ? Good luck anyway. On the fuel questions normally they quote a rate per hour ie a time. Ask again if you get stuck.
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(Original post by Old_Simon)
I noticed all these questions have one thing in common. They always divide out neatly and you get something over 15 quite often. Also learning your times tables from 11 to 19 will really help eg what are 13 x 14 ? Good luck anyway. On the fuel questions normally they quote a rate per hour ie a time. Ask again if you get stuck.
ive printed out a 1-20 times table in the hope I can learn them by Wednesday!! lol. in the meantime, any suggestions as to how I would do a big sum like this in my head?? its the big numbers that are really throwing me as I find it difficult to know what they are devisable by just by looking at them!
You travel 527 miles. How much fuel will you need if you burn 135 kgs per hour, and are travelling at 465 mph?

Thank you!
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(Original post by Redders13)
ive printed out a 1-20 times table in the hope I can learn them by Wednesday!! lol. in the meantime, any suggestions as to how I would do a big sum like this in my head?? its the big numbers that are really throwing me as I find it difficult to know what they are devisable by just by looking at them!
You travel 527 miles. How much fuel will you need if you burn 135 kgs per hour, and are travelling at 465 mph?

Thank you!
Ok. This is over 1 hour so deduct. 527-465=35+27=62

Now we need 62/465. And oh gosh both are divisible by 31 = 2/15

See how 15 keeps coming up ?

So we are going for 1 & 2/15 hours at 135 kgs an hour. = 135 + 28 = 163 kgs. Simples. I shoulda been a fighter pilot lol.
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(Original post by Old_Simon)
Ok. This is over 1 hour so deduct. 527-465=35+27=62

Now we need 62/465. And oh gosh both are divisible by 31 = 2/15

See how 15 keeps coming up ?

So we are going for 1 & 2/15 hours at 135 kgs an hour. = 135 + 28 = 163 kgs. Simples. I shoulda been a fighter pilot lol.
haha you should, thank you so much for the tips. I think I'm going to struggle in that I wouldn't see straight away that those numbers were devisable by 31, but I will look out for the 15 thing like you said! what job did you do?? something in the air I presume?
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(Original post by Redders13)
haha you should, thank you so much for the tips. I think I'm going to struggle in that I wouldn't see straight away that those numbers were devisable by 31, but I will look out for the 15 thing like you said! what job did you do?? something in the air I presume?
No I never flew anything unfortunately except a few gliders. But in "our day" lol mental arithmetic was banged into us from an early age. You need to get the 1-12 times table really fluent - I mean instantaneous. Then build from there. You soon learn tricks and short cuts. Squares like 14 x 14 etc. Or 9 x something is 10 x minus 1 x and so on. It does come but it takes practise. In the RAF or indeed any flying you do not really need this stuff except in emergencies. Then you really need it !!! In the meantime it is a useful indicator for a pilots capacity to handle a very high cockpit workload under pressure. From what I know of it 99% of flying is mental. The co-ordination is not so tricky.

In these questions though (which I have experienced in another field) there is an art in understanding how they put questions together. Eg that 62 we just did. We know the factor is an odd number. It is not divisible by 3,5,7,9,11,13,15 etc..............see how quickly it becomes clear........???

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Updated: March 5, 2014
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