SOLUTION: john has twin sisters, grace & gina. in four years john will be twice as old as the twins are now. last year grace was 2/3rds of johns age. how old are each of the siblings

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Question 755554: john has twin sisters, grace & gina. in four years john will be twice as old as the twins are now. last year grace was 2/3rds of johns age. how old are each of the siblings
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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john has twin sisters, grace & gina.
in four years john will be twice as old as the twins are now.
last year grace was 2/3rds of johns age. how old are each of the siblings
:
let j = John's age
let t = twin's age
:
"in four years john will be twice as old as the twins are now."
j + 4 = 2t
j + 4 = 2t
j = 2t
j = 2t - 4
:
"last year grace was 2/3rds of johns age."
t - 1 = 2%2F3(j-1)
multiply both sides by 3
3(t-1) = 2(j-1)
3t - 3 = 2j - 2
3t = 2j - 2 + 3
3t = 2j + 1
Replace j with (2t-4)
3t = 2(2t-4) + 1
3t = 4t - 8 + 1
3t = 4t - 7
7 = 4t-3t
t = 7 yrs old is the twin's age
;
how old are each of the siblings? they're twins they are the same age!