Answer: 6.68km/litre
Step-by-step explanation:
Distance(d) = 187km ( to 3 significant figures)
Petrol(p) = 28litres ( to 2 significant figures)
A number, x, rounded to 1 significant figure is 200
Write down the error interval for x
Calculating the lower and upper bound for both 'd' and 'p'
Upper bound 'd' = 187.5km
Lower bound 'd' = 186.5km
Upper bound 'p' = 28.5km
Lower bound 'p' = 27.5km
Therefore,
Petrol consumption (C) = d/p
Upper C = 187.5 / 28.5 = 6.57894
Lower C = 186.5 / 27.5 = 6.781818
Accuracy answer for C = (6.57894 + 6.781818) / 2 = 6.680379
= 6.68km/ litre ( to 3 significant figures)
To achieve a reasonable level of accuracy, the upper and lower bounds of P and D was used to calculate C, which was then averaged.
Using 3 significant figures ensure that we capture the C better, instead of early rounding.
