Speed Distance Time for Dummies

Hello eyes on, i have a couple of questions for you. With the what speed questions (i can see that you have explained it above) but what is the best most reliable method to work out speed. I just want to get a method squared away in my mind and work on it. For instance i will give you a few question and your working will help me.

What speed covers 14 miles in 2 hours and 48 mins?
What speed covers 76 miles in 48 mins?
What speed covers 45 miles in 1 hour and 40 mins?
What speed covers 28 miles in 48 mins?
What speed covers 17 miles in 5 hours and 40 mins?

I am just starting out with these so if you can just show me where i start with these type of questions and what is the best method.

Reply 344

If the question asks for speed then what you are looking for is how many miles (nautical miles, feet, Assyrian perches, the measure doesn't matter) you do in an hour.

So ask yourself what you would do to the time figure to make it into an hour.
Then do the same thing to the distance figure.

So - What speed covers 14 miles in 2 hours and 48 mins?

You first recognise 48 is 4/5th of an hour, because you've learnt to recognise the relationship between 60 and 12. There are 5 x 12s in 60 minutes, so in 2 hours 48 minutes there are 14 lots of 12. So to get 2 hours 48 to an hour you divide by 14 (and get 12) and then multiply by 5.

Do the same to the distance figure - 14/14x5 = 5 miles per hour

Gross error check if I did 5mph, in 2 hours and most of another hour I'd travel 2x5+ most of another 5 miles ie about 14 miles.

Reply 345

Thankyou threeportdrift that has helped me, what about the other questions, can you please please please :smile:

do them for me so i can see that method in different types of question, thank you though for what you have done so far.

What speed covers 240 miles in 16 hours? with questions such as whole numbers like this one, do the hours just divide straight into the the miles? so it would be 15?

Reply 346

hey can you check my method please.

What speed covers 45 miles in 1 hour and 40 mins?

so first i look at 40 and notice that its 2/3 of 60.

and 1 hour is 3/3 of 60. That makes 5/3.

so i look at 45 and divide it by 5 which gives me 9 then times that by 3= 27mph?

Reply 347

mudmover

Thankyou threeportdrift that has helped me, what about the other questions, can you please please please :smile:

Just think about what the question is asking. What speed covers 240 miles in 16 hours. If you are looking for a speed, you are always looking for the distance you travel in one hour - that's what speed is in the context of navigation. So it is always going to be a matter of working out how you make the time into one hour, and doing the same thing to the distance. You might like to think of it as a ratio

16 hrs>1hr as 240>x, whatever you do to 16 to get it to 1, you must do to 240 to get it to a speed (distance traveled in on hour)

16 hours, to get one hour you'd just divide by 16, so divide 240 by 16 = the answer.

You don't even have to know your 16 times table. There are at least 10 lots of 16 because 240 is bigger than 160 (10x16) so you've got 10, with 240-160 = 80 left over. Then again, because you are familiar with the numbers you know that 80 is half of 160 so the answer is going to be 5 (in fact 5 lots of 16 in 80) so 10+5 = 15.

Reply 348

Don't know if I can be bothered to do any more, the Queen stopped paying me to do this stuff ages ago :s-smilie:

What speed covers 76 miles in 48 mins?

48 is 4/5th of an hour because I recognise 48 is 4x12 and I know 5x12 in an hour
So 76/4 = no idea but I know 80/4 = 20 and 76 is one 4 less so 19
19x5 = 95
Gross error check 76 is about 3/4 and 48 is 4/5 hmmm seems about right.

What speed covers 45 miles in 1 hour and 40 mins?

I recognise 40 is 2 lots of 1/3 of an hour, so to get 1.40 to an hour I divide by 5 and multiply by 3
45 divided by 5 = 9 x 3 = 27
Gross error check - about 3/5ths of 45 - seems about right!

What speed covers 28 miles in 48 mins?

I recognise 48 minutes again!, I divide it by 4 and multiply it by 5 to make an hour.
28 divided by 4 is 7, 7x5 = 35
Gross error check - a quarter of 28 more than 28 - seems about right!

What speed covers 17 miles in 5 hours and 40 mins? A very slow one

I recognise 40 minutes as 2/3 of an hour, 5hr 40 = 17 thirds of an hour, so to make one hour I'd divide by 17 and multiply by 3.
ooh look! 17 miles! 17/17 = 1, 1x3 = 3 miles per hour
Gross error check - I knew it was going to be slow - 5.40 is nearly 6 hours, 17 miles in 6 hours is about 3 miles an hour (18/6) - Woo!

If I got any of them wrong it's because I'm dead on my feet and watching Bruce Willis :p:

Reply 349

i understand it now, thankyou, what bruce willis film you watching?

Reply 350

thank you thankyou three port that is a massive help. I i really appreciate the time you have taken to do this for me. Just out of interest what aircraft are you a nav on?

Reply 351

I have no idea what Bruce Willis film it was, they are all noisy and end up with him looking horribly sweaty and bleeding unconvincingly.

I was a Herc navigator :smile:

Reply 352

my friend chris was a nav on the hercules, dont know if you know him?

Reply 353

Don't immediately recognise the name (which you should now delete) but maybe he was on the north side while I was south side, or he is a darn sight younger than me and was on the fleet only in the last 6 years.

Reply 354

At 75 mph, how long does it take to travel 40 miles?

At 45 mph, how long does it take to travel 60 miles?

i can now do the speed ones just need a little help with the method for these.

also....at oasc how are you timed during the speed distance time questions? i heard that you get to read the questions a few times before you awnser, which sounds untrue but as i have never been i would not know.

Reply 355

stegriff

You answered 10 out of 10 questions correctly in a time of 1 minutes 43 seconds.

On average, you answered each question in 10.3 seconds

thanks for the help, getting a lot better then i was! just want to thank everyone who put up with my constant number of questions.

Reply 356

mudmover

At 75 mph, how long does it take to travel 40 miles?

At 45 mph, how long does it take to travel 60 miles?

It's all exactly the same method!

75 miles per hour means to you 75 miles in 60 minutes. You need to find how many minutes it takes to do 40 minutes. So whatever you do to 75 to make it into 40, you do the same to 60 to get the answer. Its the ratio again.

How to get 75 >40? Straight away you can see it might be fiddly as 75 is nearly 80, but isn't 80. So try 75/15 which gives you 5 and 5x8 = 40. So if you divide 60 by 15 you get 4, then multiply it by 8 and you get 32.

Gross error check - 40 is a very little bit more than half 75, the distance I'd travel in an hour, so I expect the answer to be a very little bit more than half an hour. Cx

At 45mph how long does it take to travel 60 miles. You know straight away the answer is going to be more than one hour, because you only travel 45 miles in one hour. To travel and extra 15 miles is an extra third of 45, so an extra third of an hour ie 20 minutes, so it's going to take 1 hour 20 minutes to travel 60 miles at 45 miles per hour

Reply 357

jimbo715

You arrive at your target at 00:13. You have flown 462 miles from your base at an average speed of 660 knot. What time did you depart the base?

You are ordered to land at an RAF Leeming at 14:54. The base is 90 miles away and you are travelling in the opposite direction, assuming you are flying at 360 knots and it will take 2 minutes to turn, how long will it take to get to the RAF Leeming?

Your aircraft burns 4860 lbs of fuel an hour flying at a speed of 540kts. How much fuel will you need to travel 720 miles?

A Typhoon flies a triangular navigation exercise achieving an overall average speed of 550 knots. The first leg is 500 miles at 400 knots. The second leg is 1 hour long and you fly at 700 knots. The final leg (leg 3) is 450 miles. Find the speed for the final leg and the total flight time.

An officer walks 3 miles in 1 hour. He then
travels 90 miles for 1½ hour by car and finally
42 mile by train in ½ hour. Find his average
speed for the whole journey ignoring and
waiting time.

Reply 358