Althea has 100 trading cards and Marlon has 20. Every day Althea gives Marlon one card. Use the equations "c=100-d" and "c=20+d" to model this situation. Solve the system by substitution. Explain what the solution means in this situation.

Step-by-step explanation:

c=100-d {Equation 1}c=20+d {Equation 2}{Equation 1 + Equation 2}2c=120 (-d+d= 0)So d is eliminated c=120/2c=60Althea = 60=100-d(substitute c for 60 )d=100-60d=40Check your answer by substituting both c and d60=100-40(substituting using equation 1)So 60=60Answer is correct!

C is the Althea's and Marlon's letter

D is the amount of cards that Althea gives and Marlon receives..