Which is a stretch of an exponential decay function? A: fx) = 4/5 (5/4) ^x
B: f(x) = 4/5 (4/5) ^x
C: f(x) = 5/4 (4/5) ^x
D: f(x) = 5/4 (5/4) ^x

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