How do you know that angle adb and angle bdc are supplementary

Last year, a state university received 3,560 applications from boys. of those applications, 35 percent were from boys who lived in other states. part a)how many applications did the university receive from boys who lived in other states? part b)applications to the university from boys represented 40percent of all applications. how many applications did the university receive in all? i don't how to do part b so me and plz tell how you got your answer

The border line of the linear inequality 4x + 7y < 5 is dotted true or false?

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?