Answer:
A+6+A = 20
A = 7
Step-by-step explanation:
J = number of problems Juana completed
A = number of problems Andy completed
J+A=20
J = A + 6
Replace J with A+6 in the first equation
A+6+A = 20
2A +6 = 20
Subtract 6 from each side
2A +6-6 = 20-6
2A =14
Divide by 2
2A/2 = 14/2
A = 7
Y=12.5x
because 12.5 is the constant and this is a directly proportional equation