Answer:
Sydney is 44 years old
Step-by-step explanation:
Step 1: Make a system of equations
d = s - 15
d + s = 73
Step 2: Plug in s - 15 for d in the second equation and solve
s - 15 + s = 73
2s - 15 = 73 + 15
2s / 2= 88 / 2
s = 44
Answer: Sydney is 44 years old
