Higher Plus
1st February 1980
- 1Proof of the Circle Theorems2 marks
In a circle theorem proof, a step uses the fact that OA and OB are both radii of the circle, so triangle OAB is isosceles. State the reason being quoted.
- 2Probability Equation Questions3 marks
A bag holds 9 counters, r of them red. Two are taken without replacement and P(both red) = 5/18. Work out r.
- 3Histograms2 marks
On a histogram, a 10-wide bar and a 40-wide bar have the same frequency density of 3. How many more values are in the wider class?
- 4Surds3 marks
Rationalise the denominator of 20/sqrt(2), giving your answer in its simplest form.
- 5Quadratic Inequalities3 marks
Solve x^2 + 9x + 8 < 0.
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