Please help is this undefined or 0?

Sara needs to take a taxi to get to the movies the taxi charges $4.00 for the first mile and then $2.75 for each mile after that if the total charge is $20.50 then how far was sara’s taxi ride to the movie

1. if we have 3 babies what is the probability they’re going to be all boys? 2. if we roll 2 die at the same time what is the probability of getting less than 10 on the first roll and a 5 on the second roll 3. if we have 3 babies what is the probability their is going to be 2 girls? 4. if we have 3 babies what is the probability of having no more than 1 girl? 5. it we have 3 babies and then have another 3 babies what is the probability of us having at least 1 boy and then having all girls?

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin.how many doctors use brand x aspirin