There are 9 students in a class 2 boys and 7 girls,
If the teacher picks a group of 4 at random, what is the probability that everyone in the group is a girl?

Alonso walked with his friend andy one day, and wanted to compare their speeds. alonso walked 3 miles in one hour, and andy walked 2 miles in 2 hours. complete the table to graph the relationship for each person.

Sole with work in 10 years, the average number of hours of tv watched per week by teenagers dropped from 23.9 to 21.4. find the percent of change.

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?