A class of 25 pupils takes a test. The teacher records the following: 40% of the pupils scored at least 70 marks. Of those who scored at least 70, 60% scored at least 85 marks. The rest of the class scored below 70.
(a)How many pupils scored at least 70 marks?(2)
(b)How many pupils scored at least 85 marks?(3)
(c)The teacher wants to award a prize to one pupil chosen at random from those who scored at least 70. What is the probability that the prize goes to a pupil who scored at least 85? Give your answer as a fraction in simplest form.(3)
(d)One of the pupils who scored below 70 is picked at random to receive help. How many pupils are eligible for this help and what is the probability that a particular pupil chosen at random from the whole class is one of those eligible? Give the probability as a decimal to 3 decimal places.(4)
(Total for Question 7 is 12 marks)