Question

The distance between two points on a map is 5 cm correct to the nearest centimetre.
(a) Write down the (i) least upper bound of the measurement (ii) greatest lower bound of the measurement.
(b) The scale of the map is 1 to 20 000. Work out the actual distance in real life (in kilometres) between the upper and lower bounds.

Answer 1

a) Upper-bound would be 5.49 and the lower-bound would be 4.50

b) if 1cm = 20,000 cm then the real distance between the upper and lower bounds would be equal to : \[(5.49-4.5)\times20,000 = 19,800 cm\] or ~20 km

** depending on how many significant figures you want to use, the answer to be will approach the limit of 20 kilometers between the upper and lower bounds.