Every employer shall pay to each of his employees (other than an employee to whom subsection (a)(5) of this section applies) who in any workweek is engaged in commerce or in the production of goods for commerce, or is employed in an enterprise engaged in commerce or in the production of goods for commerce, and who in such workweek is brought within the purview of this section by the amendments made to this chapter by the Fair Labor Standards Amendments of 1966, title IX of the Education Amendments of 1972 [
20 U.S.C.
1681 et seq.], or the Fair Labor Standards Amendments of 1974, wages at the following rate: Effective after December 31, 1977, not less than the minimum wage rate in effect under subsection (a)(1) of this section.