Mathematics for IGCSE & O level - Limits Of Accuracy (Section 2 - No. 12)

Calculate, to 3 significant figures, the lower bound of the distance travelled for a speed of 57 km/h for 2.5 hours, both values being to 2 s.f.

140 km

140.6 km

141 km

142.5 km

Lower bound distance = (lower bound speed) x (lower bound time) = (56.5 km/h) x (2.45 h) = 138.425 km. To 3 significant figures the answer is 138km