1. Write √72 in the form a√2.
- A6√2
- B36√2
- C3√2
- D12√2
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Answer: A. 72 = 36 × 2, so √72 = √36 × √2 = 6√2. The 36 must be square-rooted when it comes out of the root.
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Practise GCSE Maths (AQA) (AQA 8300) with 284 exam-style MCQs, each with the answer and a short explanation. Every test is marked the moment you finish and shows your score chapter by chapter, so you know what to revise next. It is free and needs no sign-up.
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Practise GCSE Maths (AQA) (AQA 8300) with 284 exam-style MCQs, each with the answer and a short explanation. Every test is marked the moment you finish and shows your score chapter by chapter, so you know what to revise next. It is free and needs no sign-up.
284 questions · 6 chapters
The questions follow the syllabus chapter by chapter. You can test the whole subject or one chapter at a time.
12 questions from the test, one or two from each chapter. Try each one, then open the answer.
Answer: A. 72 = 36 × 2, so √72 = √36 × √2 = 6√2. The 36 must be square-rooted when it comes out of the root.
Answer: A. r2 = 52 + (−12)2 = 25 + 144 = 169, so x2 + y2 = 169. The right-hand side is r2, not r (r = 13).
Answer: B. Make b the same in both: a : b = 9 : 12 and b : c = 12 : 10, so a : c = 9 : 10. Just taking the first and last numbers (3 : 5) ignores that b is different in each ratio.
Answer: C. OM = OA + ½AB = a + ½(b − a) = ½a + ½b = ½(a + b). ½(b − a) is only AM.
Answer: C. For independent events multiply: 0.3 × 0.6 = 0.18. Adding (0.9) is for mutually exclusive events with "or".
Answer: B. Use midpoints: 4 × 5 + 10 × 15 + 6 × 25 = 20 + 150 + 150 = 320, and 320 ÷ 20 = 16 minutes. Dividing by 3 (the number of classes) gives 106.7.
Answer: C. Multiply top and bottom by 3 + √5: the denominator becomes 9 − 5 = 4, so 4(3 + √5)/4 = 3 + √5. Using 9 + 5 in the denominator is the common slip.
Answer: D. Perpendicular gradient = −1 ÷ 2 = −½. Then 1 = −½ × 4 + c, so c = 3. Using −2 changes the sign but forgets to take the reciprocal.
Answer: D. V1 = 0.9 × 1000 + 50 = 950. V2 = 0.9 × 950 + 50 = 855 + 50 = 905. Adding 50 only once, after 0.92, gives 860.
Answer: B. Area factor 80/45 = 16/9, so the length factor is 4/3 and the volume factor is 64/27. 54 × 64/27 = 128 cm3. Multiplying by the area factor gives 96 cm3.
Answer: A. The probabilities of all outcomes add to 1: 1 − 0.35 − 0.4 = 0.25. 0.75 is P(red or blue).
Answer: A. The totals are 5 × 12 = 60 and 6 × 13 = 78, so the sixth number is 78 − 60 = 18.
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