A-Level MathematicsYear 2020Q4
12 4. The discrete random variable D has the following probability distribution d 10 20 30 40 50 P (D = d ) k 10 k 20 k 30 k 40 k 50 where k is a constant. (a) Show that the value of k is 600 137 (2) The random variables D1 and D2 are independent and each have the same distribution as D. (b) Find P (D1 + D2 = 80) Give your answer to 3 significant figures. (3) A single observation of D is made. The value obtained, d, is the common difference of an arithmetic sequence. The first 4 terms of this arithmetic sequence are the angles, measured in degrees, of quadrilateral Q (c) Find the exact probability that the smallest angle of Q is more than 50° (5) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________
Paper Source:9MA0_31_que_20201020.pdf
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Exam Specification Info
This question is part of the UK A-Level Mathematics syllabus. In the actual exam, structured questions typically require linking specific keywords to gain full marks. Applaa helps you drill these topics.
Syllabus levelAdvanced Level (A-Level)
SubjectMathematics
Official MarksVariable (2–6 marks)