SOLUTION: 4 years ago my father age was five times my age. at present the sum of our age is 50. what is my fathers present age? sir pls give me its step also?
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Question 830750: 4 years ago my father age was five times my age. at present the sum of our age is 50. what is my fathers present age? sir pls give me its step also?
You can put this solution on YOUR website! ---
x = father
y = son
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x - 4 = 5(y - 4)
x + y = 50
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put the system of linear equations into standard form:
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x - 4 = 5y - 20
x + y = 50
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x - 5y = -16
x + y = 50
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solution by matrix method:
x = father = 39
y = son = 11
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now by elimination:
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( x - 5y = -16 ) * -1
x + y = 50
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-x + 5y = 16
x + y = 50
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add the system:
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6y = 66
y = 11
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x + 11 = 50
x = 39
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solution by elimination method:
x = father = 39
y = son = 11
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now by substitution:
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x - 5y = -16
y = 50 - x
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x - 5(50 - x) = -16
x - 250 + 5x = -16
6x = 234
x = 234/6
x = 39
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y = 50 - 39
y = 11
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solution by substitution method:
x = father = 39
y = son = 11
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the methods agree !
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