CAIE IGCSE Mathematics Extended E1.10 Limits of Accuracy Questions

Practise finding bounds from rounded measurements and using them in lengths, speeds, areas, density and formula calculations.

Exam points

choose the correct upper or lower bound for each rounded measurement in the calculation
calculate maximum or minimum values by selecting bounds in formulae
apply bounds to perimeter, area, volume or remaining-length calculations from context

Covered syllabus points

E1.10.1 Give upper and lower bounds for data rounded to a specified accuracy.E1.10.2 Find upper and lower bounds of the results of calculations which have

[Maximum number: 2]

Solve the equation.

\frac{1-x}{3}=5

-14
M1 for $1-x=3\times5$ or better, or $\frac{x}{3}=5-\frac{1}{3}$ or better.

[Maximum number: 3]

A rectangle has an area of $9400 \mathrm{~cm}^{2}$ , correct to the nearest $100 \mathrm{~cm}^{2}$ .

The length of the rectangle is 80 cm , correct to the nearest 10 cm .
Calculate the upper bound of the width of the rectangle.

126 nfww
M2 for $\frac{9400+50}{70\text{ to }80}$ or $\frac{9400\text{ to }9500}{80-5}$
or M1 for 9350 or 9450 or 75 or 85 seen

[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

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Covered syllabus points

Question 1

Question 2

Question 3