The sum of brian's and rihanna's ages is 41. The difference between two times brian's age and rihanna's age is 13. How old is rhianna

Can someone me and plz do the problem

Powerful women's group has claimed that men and women differ in attitudes about sexual discrimination. a group of 50 men (group 1) and 40 women (group 2) were asked if they thought sexual discrimination is a problem in the united states. of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem. if the p-value turns out to be 0.035 (which is not the real value in this data set), then at = 0.05, you should fail to reject h0. at = 0.04, you should reject h0. at = 0.03, you should reject h0. none of these would be a correct statement.

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?