# A level maths help needed!!!

#1
A car is available in a number of models.
30% are three door hatch backs, 55% are 5 door hatchbacks and the remainder are convertibles.
Of the three door hatcbacks: 60% have a 1.1 litre engine, 15% have a 1.4 litre engine and 25% have a diesel engine.
Corresponding figures for five door hatchbacks: 15%, 55% and 30%
For convertibles: 5%, 85% and 10%

Find the probability that two of these cars (chosen at random) have the same engine.

I don't understand how to find this, even though I have drawn a tree diagram.
0
2 years ago
#2
(Original post by Juliakinga)
A car is available in a number of models.
30% are three door hatch backs, 55% are 5 door hatchbacks and the remainder are convertibles.
Of the three door hatcbacks: 60% have a 1.1 litre engine, 15% have a 1.4 litre engine and 25% have a diesel engine.
Corresponding figures for five door hatchbacks: 15%, 55% and 30%
For convertibles: 5%, 85% and 10%

Find the probability that two of these cars (chosen at random) have the same engine.

I don't understand how to find this, even though I have drawn a tree diagram.
Initially work out the probability of a three-door with a 1.1 litre then a 1.4 litre then deal then repeat for the two other types of car. To help convert the percentages into fraction to get easier numbers. Then extend the tree diagram to factor in the choice of a second car but remember you only need to work out the probability of the same engine so there is still three options
0
#3
(Original post by Theghostwrighter)
Initially work out the probability of a three-door with a 1.1 litre then a 1.4 litre then deal then repeat for the two other types of car. To help convert the percentages into fraction to get easier numbers. Then extend the tree diagram to factor in the choice of a second car but remember you only need to work out the probability of the same engine so there is still three options
thank you!
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Year 12s - where are you at with making decisions about university?

I’ve chosen my course and my university (21)
31.82%
I’ve chosen my course and shortlisted some universities (25)
37.88%
I’ve chosen my course, but not any universities (2)
3.03%
I’ve chosen my university, but not my course (3)
4.55%
I’ve shortlisted some universities, but not my course (4)
6.06%
I’m starting to consider my university options (9)
13.64%
I haven’t started thinking about university yet (1)
1.52%
I’m not planning on going to university (1)
1.52%