Please help me on why it can or cannot be non planar with a proof aswell

A(t)=728(1+0.04)^t how much money did aditya originally invest

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.