options: 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.

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.
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: 1