
Answer:
The answer to your question is Advance = $35 and same-day = $40
Step-by-step explanation:
Advanced = a
Same-day = s
Equations
            a +   s  = 75        ----- (I)
         20a + 35s = 2100       ----- (II)
Process
1.- Solve the equations by elimination.
Multiply equation I by -20
           -20a - 20s = -1500
           20a + 35s = 2100
Simplify
            0  + 15s = 600
Solve for s          s = 600/15
                  s = $ 40    Â
Substitute "s" in equation I to find "a"
            a  +  40  = 75
Solve for a
            a   = 75  - 40
            a = 35