Answer:
A. x=y-4, x+y=16
C. x=y-4, x+y=16
Step-by-step explanation:
• Let Sue's age = x
Mary is 4 years older than Sue, therefore:
• Mary's age, y = x+4

Next, the sum of their ages is 16. This gives:

Therefore, the equation is:

The correct choices are A and C.