16 people like tea and coffee but do not like milk. 21 people like coffee and milk. 24 people like tea and milk. 40 people like coffee. 1 person likes only milk. Sami selects at random one of the 50 people. (a) Work out the probability that this person likes tea. ........................................................... (4) (b) Given that the person selected at random from the 50 people likes tea, find the probability that this person also likes exactly one other drink. ........................................................... (2) (Total for question = 6 marks) Proportion Things to remember: Start by checking the question for squares, cubes and roots; is directly proportional to y” like x y or x = ky “x α is inversely proportional to y” looks like x or x = “x α Questions: 1. The shutter speed, S, of a camera varies inversely as the square of the aperture setting, f. When f = 8, S = 125 (a) Find a formula for S in of f.
16 people like tea and coffee but do not like milk. 21 people like coffee and milk. 24 people like tea and milk. 40 people like coffee. 1 person likes only milk. Sami selects at random one of the 50 people. (a) Work out the probability that this person likes tea. ........................................................... (4) (b) Given that the person selected at random from the 50 people likes tea, find the probability that this person also likes exactly one other drink. ........................................................... (2) (Total for question = 6 marks) Proportion Things to remember: Start by checking the question for squares, cubes and roots; “x is directly proportional to y” like x α y or x = ky “x is inversely proportional to y” looks like x α or x = Questions: 1. The shutter speed, S, of a camera varies inversely as the square of the aperture setting, f. When f = 8, S = 125 (a) Find a formula for S in of f.
Revision_Guide_Aiming_for_Grade_9.docx