Answer:
Marco is 21
Step-by-step explanation:
Let the sister's age = x
Marco's age = 2*x - 5
x + 2x - 5 + 14 = 48 Combine the left side of the equation.
3x + 9 = 48 Subtract 9 from both sides
3x = 48 - 9
3x = 39 Divide by 3
x = 39/3
x = 13
So the sister is 13
Marco = 2x - 5 = 2*13 - 5
Marco = 21