SOLUTION: Shelly is three years older than Michele. Four years ago the sum of their ages was 67. Find the age of the person now. Can you give me a basic formula to solving most Age Word Prob

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Question 276430: Shelly is three years older than Michele. Four years ago the sum of their ages was 67. Find the age of the person now. Can you give me a basic formula to solving most Age Word Problems.
Found 2 solutions by stanbon, oberobic:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Shelly is three years older than Michele. Four years ago the sum of their ages was 67. Find the age of the person now.
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Equation:
S = M+3
(S-4)+(M-4) = 67
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Modify the 2nd equation:
S + M = 67+8 = 75
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Substitute for "S" and solve for "M":
M+3 + M = 75
2M = 72
M = 36 (Michele's age now)
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Since S = M+3, S = 39 (Shelly's age now)
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Cheers,
Stan H.

Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
S = Shelly's age
M = Michele's age
S = M + 3 :: Shelly is 3 years older than Michele.
.
"Four years ago" their ages will be S-4 and M-4. The sum of their ages was 67.
So, today we can say
S-4 + M-4 = 67
S + M -8 = 67
S + M = 75
.
Substitute S = M+3
.
(M+3) + M = 75
2M + 3 = 75
2M = 72
M =36
S = M+3 = 39
.
Four years ago their ages were:
S = 39 -4 = 35
M = 36 - 4 = 32
.
Checking if the sum 4 years ago = 67.
35 + 32 = 67
Yes.
.
Answer:
Shelly is 39, and Michele is 36.
.
Done