# maths question help limits of accuracy

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#1
I have this question in my homework and i cannot work out what I am missing, any help would be fabulous! thanks

Distance = 187km to 3sf
petrol = 28l to 2sf
consumption is c = d divided by p.
consider bounds of accuracy to work out c.

187km ± 0.5 = 187.5km or 186.5km
upper bound of distance 187.5km
28l ±0.5 = 27.5l or 28.5l
upper bound of fuel consuption 28.5litres
Upper bound km ÷ upper bound fuel used
187.5 ÷ 28.5 = 6.579km/l
therfore 6.579km/l = 187.5km ÷ 28.5l

what am I missing??

thank you !
0
3 years ago
#2
(Original post by autobotjtb)
I have this question in my homework and i cannot work out what I am missing, any help would be fabulous! thanks

Distance = 187km to 3sf
petrol = 28l to 2sf
consumption is c = d divided by p.
consider bounds of accuracy to work out c.

187km ± 0.5 = 187.5km or 186.5km
upper bound of distance 187.5km
28l ±0.5 = 27.5l or 28.5l
upper bound of fuel consuption 28.5litres
Upper bound km ÷ upper bound fuel used
187.5 ÷ 28.5 = 6.579km/l
therfore 6.579km/l = 187.5km ÷ 28.5l

what am I missing??

thank you !
Are you working out the best possible fuel consumption? If so I would be using the upper bound for distance (max distance) and the lower bound for fuel (least fuel), so 187.5/27.5.

The worst possible fuel consumption would be lower bound for distance/upper bound for fuel.
1
#3
Thanks! I will give that a try
0
3 years ago
#4
Max C is where D is max and P is min
Min C is where D is min and P is max

Think about eating a slice of pie, if u have a large piece and eat a small amount ( u have a max amoun left) vice versa
1
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