Amira is twice as old as her cousin pam. nine years ago, their age combined ages was 18. what are their present ages?

pl very important

How much orange juice do you need to make 2 servings of lemony orange slush?

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

Can someone show me step by step how to do this?