What are the solutions to the following system?

The standard distance between studs in a house is 1.5 feet. if you have a set of blueprints for a house that mark every 1.5 feet with 2 in., by how many inches will a 13-foot wall be represented?

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.

Jordan got 27 out of 90 correct on his test . what fraction of the marks did her get correct