You are Here: Home >< GCSEs

# Help on probability Q watch

1. I'm normally alright with probabilities, but this one I just can't get my head around it, any help would be appreciated!

Here is the question: The probability that Rob wakes up early at the weekend on either a Saturday or a Sunday but not both is 0.42.
The probability that he wakes up early is the same on both Saturday and Sunday.
What are the two possible answers for the probability of him waking up late on one of the days?

Also, helps on drawing the tree diagram would be appreciated.
2. Okay. Let's start with what you are given. I see that you have realised to draw a tree diagram. What I want you to think about is that the question says the probability of waking early on EITHER saturday or sunday BUT NOT BOTH is 0.42....This means what? What will the probability be on waking up early on both days? Remember that probability is always out of 1. After you do this, we can continue.
3. hope this helps

(Original post by Eldoxxy)
I'm normally alright with probabilities, but this one I just can't get my head around it, any help would be appreciated!

Here is the question: The probability that Rob wakes up early at the weekend on either a Saturday or a Sunday but not both is 0.42.
The probability that he wakes up early is the same on both Saturday and Sunday.
What are the two possible answers for the probability of him waking up late on one of the days?

Also, helps on drawing the tree diagram would be appreciated.
4. (Original post by bpn365)
hope this helps
That's great!
Thanks a lot for the tree diagram!

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 15, 2017
Today on TSR

### Congratulations to Harry and Meghan!

But did you bother to watch?

Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE