Maths question ..not homework

[silverfoxcc]

This has been puzzling me for years and i still cannot work out a formula,,if there is one. Now with and on board mpg read out it is even more frustrating

I am not sure if the actual amount og fuel at anytime during the journey has an input

At start of journey the ave mpg was reading 33.7

After travelling 150 miles it now is 40.4


What was my mpg in those 150 miles to increase the mpg to the new amount?

[Scrump]

You would need to know over what distance the 33.7 average was recorded,

[r159]

Scrump said:

You would need to know over what distance the 33.7 average was recorded,

Yep, the calculation requires the total miles travelled, otherwise you have two variables in the equation…and you’re knackered.

[The spinner of plates]

You can’t work out the formula because you’ve not got enough hard data points.

[Octoposse]

The spinner of plates said:

You can’t work out the formula because you’ve not got enough hard data points.

But you could draw a graph - range of previous distances run on the x-axis, derived “new” mpg on the y.

[The spinner of plates]

Octoposse said:

The spinner of plates said:

You can’t work out the formula because you’ve not got enough hard data points.

But you could draw a graph - range of previous distances run on the x-axis, derived “new” mpg on the y.

Exactly that.
You’d need the data of how many miles the start ave mpg of 33.7 was accrued over.
Whether it’s 100 or 1,000 makes the difference. Without that, no way of knowing.

[TwigtheWonderkid]

The spinner of plates said:

Octoposse said:

The spinner of plates said:

You can’t work out the formula because you’ve not got enough hard data points.

But you could draw a graph - range of previous distances run on the x-axis, derived “new” mpg on the y.

Exactly that.
You’d need the data of how many miles the start ave mpg of 33.7 was accrued over.
Whether it’s 100 or 1,000 makes the difference. Without that, no way of knowing.

Indeed. If the 33.7 average was achieved by driving the car off the drive and on to the street, say 5 metres , it's fair to say the average mpg for the next 150 miles was almost bang on 40.4.

[silverfoxcc]

Apologies for the omission the mileage was 138 prior to the journey

[BigBen]

silverfoxcc said:

This has been puzzling me for years and i still cannot work out a formula,,if there is one. Now with and on board mpg read out it is even more frustrating

I am not sure if the actual amount og fuel at anytime during the journey has an input

At start of journey the ave mpg was reading 33.7

After travelling 150 miles it now is 40.4


What was my mpg in those 150 miles to increase the mpg to the new amount?

A = 138 / 33.7 = Gallons used in first part of journey
B = (150+138) / 40.4 = Gallons used in total miles

C = B-A = Gallons used in second part of journey

C / 150 = mpg across the 150 miles.

Ben

[TwigtheWonderkid]

33.7 x 138 = 4650.6
40.4 x (138 +150) = 40.4 x 288 = 11635.2

11635.2 - 4650.6 = 6984.6

6984.6/150 = 46.564. So that's your MPG over the 2nd journey of 150 miles, 46.564 mpg.

Edited by TwigtheWonderkid on Sunday 3rd October 19:05

[silverfoxcc]

Thanks lads

Been niggling me for quite a while !!!