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Three years ago,a father was three times as old as his so.in five years time,the father will be twice as old as his son,what will be the sum of their ages in four years​

User Tangerine
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1 Answer

6 votes

let f = father's present age, let s = son's

:

write an equation for each statement, simplify

:

Three years ago a father was thrice as old as his son

f - 3 = 3(s-3)

f - 3 = 3s - 9

f = 3s - 9 + 3

f = 3s - 6

in 5 years time the father will be twice as his son

f + 5 = 2(s+5)

f + 5 = 2s + 10

f = 2s + 10 - 5

f = 2s + 5

replace f with 3s - 6, from the 1st statement

3s - 6 = 2s + 5

3s - 2s = 5 + 6

s = 11 yrs is the son's age

find the fathers age

f = 3(11) - 6

f = 33 - 6

f = 27 yrs is the father's age

:

what will be the sum of their age in four years

27+4 + 11+4 = 46

User ItzMEonTV
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