Explain the concept of overtime pay under the FLSA

Employees covered by the Fair Labor Standards Act (FLSA) are entitled to overtime pay at one-and-a-half times their regular pay rate, for hours worked in excess of forty hours per workweek in addition to being entitled to earn the minimum wage. As with the minimum wage, regulations have been developed to compute the hourly wages of workers paid by commission, piece-rate, and so forth for the purpose of calculating overtime pay. The Portal to Portal Act of 1947, which amended the FLSA, provides that preliminary or post work activities are to be included in compensable time only if they are called for under contract or industry custom or practice.?