What is the slope and y intercept

Me i’m stuck on all these questions besides the two bottom ones

Asalsa recipe uses green pepper, onion, and tomato in the extended ratio 3: 5: 7. how many cups of tomato are needed to make 105 cups of salsa? a. 7 b. 21 c. 35 d. 49

There are 18 female students and 16 male students in a class. which of the following expresses the ratio of female students to male students in simplest form? а) 10 b) 9 to 8 c) 8: 9 d)18/16