an antique artifact is four times older than an antique book. in 200 years the artifact will be three times older than the book. how old is the artifact now? pls help

For a field trip to the zoo, 4 students rode in cars and the rest filled nine busess. how many students were in each bus if 472 students were on the trip

Can some one me with these questions

Select the margin of error that corresponds to the sample mean that corresponds to each population: a population mean of 25, a standard deviation of 2.5, and margin of error of 5%