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put this solution on YOUR website!Sara = s
John = j
1) If 3 years ago sara was 2 times john's age...
1) s - 3 = 2j
2) and 9 years from now she is 1.5 times john's age...
2) s - 9 = 1.5j
...how old are they now?
Step 1
Isolating s in equation 1):
s - 3 = 2j | +3
s = 2j + 3
Step 2
Substituting s with 2j+3 in equation 2):
s - 9 = 1.5j
2j + 3 - 9 = 1.5j
2j - 6 = 1.5j | -2j
-6 = -0.5j | : -0.5
12 = j → John is 12 years old.
Step 3
Substituting j with 12 in equation 1):
s - 3 = 2j
s - 3 = 2 ∙ 12
s - 3 = 24 | +3
s = 27 → Sara is 27 years old.
Step 4
Validating solutions by substituting s with 27 and j with 12 to check if both sides of the equations are really equal:
1) s - 3 = 2j
1) 27 - 3 = 2 ∙ 12
1) 24 = 24
2) s - 9 = 1.5j
2) 27 - 9 = 1.5 ∙ 12
2) 18 = 18
As both sides of each equation are equal s = 27 and j = 12 are valid solutions.
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