SOLUTION: 40. Michael’s age is seven-tenths of Richard’s age. In four years Michael’s age will be eight-elevenths of Richard’s age. How old is Michael now?

Algebra ->  Customizable Word Problem Solvers  -> Age -> SOLUTION: 40. Michael’s age is seven-tenths of Richard’s age. In four years Michael’s age will be eight-elevenths of Richard’s age. How old is Michael now?       Log On

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Question 926444: 40. Michael’s age is seven-tenths of Richard’s age. In four years Michael’s age will be eight-elevenths of Richard’s age. How old is Michael now?

Found 2 solutions by TimothyLamb, MathTherapy:
Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
x = mike age now
y = rich age now
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x = (7/10)y
x + 4 = (8/11)(y + 4)
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put the system of linear equations into standard form
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x - (7/10)y = 0
x + 4 = (8/11)y + (8/11)4
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x - (7/10)y = 0
x = (8/11)y + 32/11 - 44/11
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x - (7/10)y = 0
x - (8/11)y = -12/11
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x - 0.7y = 0
x - 0.72727272727y = -1.0909090909
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copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = mike age now = 28
y = rich age now = 40
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Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

40. Michael’s age is seven-tenths of Richard’s age. In four years Michael’s age will be eight-elevenths of Richard’s age. How old is Michael now?

Let Richard's current age, be R
Then Michael's current age = %287%2F10%29R, or 7R%2F10
Therefore, we get: M+%2B+4+=+%288%2F11%29%28R+%2B+4%29
M+%2B+4+=+8%28R+%2B+4%29%2F11
11%287R%2F10%29+%2B+44+=+8R+%2B+32
77R%2F10+-+8R+=+-+44+%2B+32
77R - 80R = - 440 + 320 ------ Multiplying by LCD, 10
- 3R = - 120
R, or Richard's current age = %28-+120%29%2F%28-+3%29, or 40 years-old
Michael's current age: %287%2F10%2940, or %287%2Fcross%2810%29%294cross%2840%29, or highlight_green%2828%29 years-old