A brand of ballpoint pen comes in four colors, with fine or regular point, and with standard, deluxe, or executive styling. How many different versions of the pen are there?

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