Please answer asp worth 16 points

Which graph represents the following piecewise defined function?

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of

The sum of 5consecutive even numbers is 100. what is the first number in this sequence?