(ALGEBRA 2) Hi, So I'm struggling with these last 4 questions, Can Anyone help me?

In a school 2/3 of the students study a language of those who study a language 2/5 study french

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

Rosy waxes 2/3 of her car with 1/4 bottle of car wax.at this rate,what fraction of the bottle of car wax will rosey use to wax her entire car