Answer:

12 yrs and a half.

Step-by-step explanation:

tina = X

grace = Y

equation 1

X + Y = 27

equation 2

X = Y + 2

substitute eq2 to eq1

Y + 2 + Y = 27

2Y = 27 - 2

2Y = 25

divide both sides with 2

Y = 12.5 or 12 years and a half.

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