A man's age is three times the sum of the ages of his two sons. After 5 years, his age will be twice the sum of the ages of his two sons. Find the age of the man.(Linear equations in two variables)
arunadeepak1234:
ans. is 45. i wanna know theprocess
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Answers
Answered by
217
Let the Man's age be M years.
Let the Sum of ages of both Children be C years.
Man's age M = 3 C = 3 times the sum of sons' ages.
M+5 = Man's age after 5 years = 2 (C+10) ,as each child's age increases by 5 years. and their sum increases by 10 years.
So, M = 3 C
M + 5 = 2 (C +10) = 2 C + 20
Substitute 1st equation in the 2nd.
3 C + 5 = 2 C + 20
C = 15 years
M = 45 years
The mans' age now is 45 years and sum of children's age is 15 years now.
Let the Sum of ages of both Children be C years.
Man's age M = 3 C = 3 times the sum of sons' ages.
M+5 = Man's age after 5 years = 2 (C+10) ,as each child's age increases by 5 years. and their sum increases by 10 years.
So, M = 3 C
M + 5 = 2 (C +10) = 2 C + 20
Substitute 1st equation in the 2nd.
3 C + 5 = 2 C + 20
C = 15 years
M = 45 years
The mans' age now is 45 years and sum of children's age is 15 years now.
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Answered by
164
age of 1st son x
2 nd son y
man age 3x +3y
after 5 years .......
3x + 3y + 5 = 2(x + y + 10 )
3x + 3y +5 = 2x + 2y +20
x + y = 15
man age = 3(x+y)
= 3X 15
45
2 nd son y
man age 3x +3y
after 5 years .......
3x + 3y + 5 = 2(x + y + 10 )
3x + 3y +5 = 2x + 2y +20
x + y = 15
man age = 3(x+y)
= 3X 15
45
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