CAIE IGCSE Mathematics Extended E1.10.2 Find Upper and Lower Bounds of the Results of Calculations Which Have Questions

Practise selecting input bounds that maximise or minimise a formula and calculating rigorous bounds for perimeter, area, speed and rates.

Exam points

derive each input interval from its stated rounding accuracy before using the formula
maximise a positive quotient with the numerator's upper bound and denominator's lower bound
choose all upper or lower dimensions appropriately for sums, products, areas and perimeters

[Maximum number: 3]

A bus travels 440 km , correct to the nearest 10 km . The time taken to complete the journey is 6 hours, correct to the nearest half hour.

Calculate the lower bound of the speed of the bus.
km/h [3]

69.6
M2 for $\frac{430\text{ to }440}{6+0.25}$ or $\frac{440-5}{6\text{ to }6.5}$ oe
or M1 for 440+5 oe or 440-5 oe or 6+0.25 oe or 6-0.25 oe seen

All question bank results loaded

CAIE IGCSE Mathematics Extended E1.10.2 Find Upper and Lower Bounds of the Results of Calculations Which Have Questions question 1