options: Compute unit rates associated with ratios of fractions, including ratios of lengths, areas and other quantities measured in like or different units. For example, if a person walks 1/2 mile in each 1/4 hour, compute the unit rate as the complex fraction 1/2/1/4 miles per hour, equivalently 2 miles per hour.

Recognize and represent proportional relationships between quantities.

Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.
problem_activity: Task
There are 270 students at Colfax Middle School, where the ratio of
boys to girls is 5:4. There are 180 students at Winthrop Middle
School, where the ratio of boys to girls is 4:5. The two schools
hold a dance and all students from both schools attend.  What
fraction of the students at the dance are girls?


correct_option_index: 2