CAN YOU HELP ME PLZ?

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 radius of the sphere is 10 units .what is the approximate volume of the sphere use π=3.14

The minimum height for riding on the super screaming spinner at the theme park is 52 inches. which of the following expressions shows the height to ride?