PLEASE ANSWER THESE 2 QUESTIONS ASAP!!!!!!!!!!!!!!!!!!!!!

During a scuba dive, Lainey descended to a point 20 feet below the ocean surface. She continued her descent at a rate of 20 feet per minute. Write an inequality you could solve to find the number of minutes she can continue to descend if she does not want to reach a point more than 100 feet below the ocean surface.

How can you recognize whether a real world situation should be represented by an equation or an inequality?