A bag of counters is used for a probability experiment.
(a)A bag contains counters that are either black or white only. The probability of picking a black counter is 0.6. There are 18 black counters in the bag. How many counters are there in the bag altogether?(2)
(b)5 more white counters are added to the bag, and no counters are removed or added of any other colour. Find the new probability of picking a black counter, giving your answer as a fraction in its simplest form.(3)
(Total for Question 24 is 5 marks)