Please help the question is in the picture x

Suppose i flip two identical coins. what is the probability that i get one head and one tail?

What is the missing step in this proof ?

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