sep 16 q7 part ii d and e

Hi all,

Have done this question and was a little surprised by the workings
for example part d is essentially looking for

P(Countryside| no claims OR one claim)

i would have done this as

P(Countryside| no claims OR one claim)= P(Countryside C no claims)/P(no claims) + P(countryside C one claim)/P(one claim)

but the solutions seem to do the route of

P(Countryside| no claims OR one claim) = P(countryside and no claims OR countryside and one claim)/P(no claims OR one claim)

just for my notes, have i understood this correctly? is there a reason why we do not split up the fraction as i have done?

thanks
molly

 

ah, thank you