Can you explain where they got EC and ES from and how did they get their number for the table . Help

EXAMPLE 1 GIVEN: CE 4510 hand out-02 ex et Modele 2 - MATERIALS NW CONCRETE f = 4,000 psi GR 60 STEEL - SECTION W/ REINFORCEMENT EXAMPLE 4 GIVEN: 18" 15" 319 6=12 h=18 REQ'D: SAME AS EXAMPLE 1 -DETERMINE CRACKING MOMENT Mar WITH THE "TRANSFORMED AREA" METHOD SOLUTION Mcr = fr Iut J= Mc = fr I As = 3 (1 in) = 3in Ec* 57,043,600 psi E = 29,000 Ksi n = Es 29,000 Ksi = = 8.0 Ec 3604 ksi IS" 389 COMPRESSION AND I =fr TENSION 12" (n-1) As SECTION TRANSFORMED SECTION STRESSES PART SECTION g" 216 1944 TRANSFORMED CONCRETE Ac = (n-1) As = 7.0 (3in) = 21.in Ji (in) Ai (in) Aii (n") Ai (gi-) (ins) I() 5832 61. 41-1812=9 TRANSF. CONCRET CONCERT 3" 21 63 628 NEGLECT 4223 237 2007 689 5832 y= Aiyi 2007m = 8.471 237 in' IVE I; +[Ai (yi-) = 5032 in" + 689 in 4 = 6521.ink Mar = 474 psi 103 6521 in 365 x 16-in = 30.4 K-ft (NOTE: +17% from EXAMPLE 1) 8.47in