SOLUTION: John is 4 times as old as Martha. Five years ago the sum of their ages was 50. how old are they now? Thanks Michael

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Question 835574: John is 4 times as old as Martha. Five years ago the sum of their ages was 50. how old are they now?
Thanks Michael
Answer by hovuquocan1997(83) About Me  (Show Source):
You can put this solution on YOUR website!
Let john's age be "x" and Martha's age be "y"
Based on the question, you have the system of equation
x = 4y
(x-5) + (y-5) = 50 (because it's five years ago)
Then change them to standard form and you have
x-4y = 0
x + y = 60
Now let's solve :)
Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++1%5Cx+%2B+-4%5Cy+=+0%2C%0D%0A++++1%5Cx+%2B+1%5Cy+=+60+%29%0D%0A++We'll use substitution. After moving -4*y to the right, we get:
1%2Ax+=+0+-+-4%2Ay, or x+=+0%2F1+-+-4%2Ay%2F1. Substitute that
into another equation:
1%2A%280%2F1+-+-4%2Ay%2F1%29+%2B+1%5Cy+=+60 and simplify: So, we know that y=12. Since x+=+0%2F1+-+-4%2Ay%2F1, x=48.

Answer: system%28+x=48%2C+y=12+%29.

There you go, John is 48 and Martha is 12
TA-DAH
:D