The prepasitiens p,q,r and s are dened by p: Mary takes the train : Mary walks r. Mary rides her bicycle 5: Mary drives her car Express the following...

For Question 2 I have the following answers:

i) If Mary doesn't take the train and walk, she rides her bicycle or drives her car.

ii) Mary takes the train or walks if and only if she drives her car and doesn't ride her bike

iii) If Mary doesn't ride her bicycle or drive her car, she walks or doesn't take the train

iv) If Mary neither walks nor takes the train. she drives her car or rides her bicycle.

I don't feel confident in these answers- iii) especially.

Any help would be appreciated