Select all the properties that the set (-1,1) is closed under

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

Scarlet bought three pairs of sunglasses and two shirts for $81 and paula bought one pair of sunglasses and five shirts for $105 what is the cost of one pair of sunglasses and one shirt?

Which ratios are equivalent to 10: 16? check all that apply. 30 to 48 25: 35 8: 32 5 to 15