Student Challenge Friday

Here is your Friday challenge:

A bag contains only red, yellow and blue lollies. The probability of picking a red lolly is 0.25 and the probability of picking a yellow lolly is 0.40. What is the least number of lollies that could be in the bag?

Extra:

What would be the probability of picking a blue lolly?

Write your answer in the comments with your name and class or ask your teacher to send me a photo of your work :-)

Below are photos of Room 6 working out the problem:

Room 6 found this a really challenging problem.  We decided that if red was 0.25 and yellow was 0.4, then the probability of a blue lolly was 0.35.  From there, we got a bit stuck – most of us turned these decimals into fractions and then didn’t know where to go from there.

With a bit of help from Mr Dawson, we figured out that in a bag of 100 lollies, there would be 25 red, 40 yellow and 35 blue.  We then decided to divide all those numbers by the highest common factor we could find, which was 5.  That reduced the numbers to 5 red, 8 yellow and 7 blue, which means the smallest amount of lollies in a bag was 20.