A bag contains 5 blue marbles and 5 red marbles. If marbles are NOT replaced after being selected from the bag, what is the probability (in percentage) of picking 2 red marbles? Give your answer to one decimal place.
As there are a total of 10 marbles in the bag, then the probability of picking a red marble is 5/10. When the next marble is selected, there are only 9 marbles left in the bag since the red marble has not been replaced. As there are only 4 red marbles left, the probability of picking another red marble is 4/9. To get the total probability, these two individual probabilities can be multiplied to give 20/90 which can be reduced to 2/9. As the question asks for this fraction to be given as a percentage to one decimal place, calculate 2/9 on your calculator and then multiply by 100 to give 22.2%.
PB
Related Maths GCSE answers
All answers ▸How does Pythagoras Theorem work?
Text books are stored on two shelves. Each shelf is 0.72m long. Each textbook is 30 millimetres wide. Could 50 textbooks be stored on these shelves? (3 marks)
Sarah asked 20 people at a tennis tournament how they travelled there. She found that 13 of them travelled by car. Estimate how many of the total 2000 people at the tournament travelled by car.
Kelly is trying to work out the two values of w for which 3w - w^3 = 2 Her values are 1 and -1 Are her values correct? You must show your working.