mai is going for a walk, she walks at a constant speed for 20 minutes. she takes a break for 5 minutes before turning around and walking back home, she walks faster than she did before

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