EDEXCEL GCSE MATHS HARD Probabilities Help.

Basit2010

Generally OK on maths but end up loosing marks on the 'harder' probability questions like below:

I have the answers but would like to know how to get to them? Many thanks +1 to best answer.

Reply 1

Micky76

Original post by Basit2010

Generally OK on maths but end up loosing marks on the 'harder' probability questions like below:

I have the answers but would like to know how to get to them? Many thanks +1 to best answer.

Do you want me to just post the solutions or solutions with an explanation?

Reply 2

Basit2010

Original post by Micky76

Do you want me to just post the solutions or solutions with an explanation?

With an explanation please as i already have the mark scheme but do not know how they got to the answer.

thanks

Reply 3

TenOfThem

Q22
P(star star) = 4/9 * 3/8 = 1/6
Can you work out P(heart heart)

Reply 4

TenOfThem

Q18

Your possible options are

Milk, not
not, Milk
Milk, Milk
not, not

So you want 1-P(not,not)

For P(not,not) you need fraction*fraction

Just remember that the second fraction is 10/14 as you already have a not in your hand

Reply 5

Anythingoo1

First question, probability of winning occurs if you get 2 hearts or 2 stars. P(2stars) = 4/9 x 3/8 = 1/6. P(2hearts) = 3/9 x 2/8 = 1/12

Probability of winning occurs when you get EITHER 2 hearts or 2 stars, so you add the 2 probabilities and voila! (answer is 1/4)

Please, please don't tell me I did that wrong :/

Reply 6

TenOfThem

Q20

You can start with a number of student

I would suggest 100 boys and 200 girls

Work out the number who like sports using your fractions then put it /300