Sara and Lane share a 30-ounce box of cereal. By the end of the week, Sara has eaten 1 10 of the box, and Lane has eaten 2 5 of the box of cereal. How many ounces are left in the box?

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