4024/23 May/Jun 2025, Question 21: Upper and Lower Bounds
Cambridge O Level Mathematics 4024 · Paper 23 (Calculator) · Calculator · 3 marks
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The question, in short
A rectangle has width 5.4 cm and perimeter 26.4 cm, each rounded to the nearest 0.1 cm. Find the greatest possible width and the smallest possible length.
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Part (a) · 1 mark
State the largest value the width could have been before rounding to 5.4 cm.
- 1Half of 0.1 = 0.05
- 2Upper bound = 5.4 + 0.05 = 5.45 cm
Answer5.45
Part (b) · 2 marks
Using the perimeter rounded to 26.4 cm, work out the smallest possible value of the rectangle's length.
- 1Lower bound of perimeter = 26.35, upper bound of width = 5.45
- 2Length = (26.35 − 2 × 5.45)/2
- 3= 15.45/2 = 7.725 cm
Answer7.725
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Also searched as: 4024/23/M/J/25 · 4024_s25_qp_23 · 4024 s25 23 · question 21.
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