Problema Solution
Two years ago Sam was 4 times as old as Dave was. Two years from now Sam will be 3 times as old as Dave will be. In how many years from now will Sam be twice as old as Dave?
Answer provided by our tutors
let
s = the present age of Sam
d = the present age of Dave
Two years ago Sam was 4 times as old as Dave was
s - 2 = 4(d - 2)
Two years from now Sam will be 3 times as old as Dave will be:
s + 2 = 3(d + 2)
by solving the system of equations:
s - 2 = 4(d - 2)
s + 2 = 3(d + 2)
we find:
s = 34
d = 10
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let x represents the number of years for now when Sam will be twice as old as Dave:
34 + x = 2(10 + x)
by solving we find:
x = 14 years
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after 14 years Sam will be twice as old as Dave.