SOLUTION: mila is 7 years older than her sister lina. in 3 years,she will be 17 years more than one-fifth as old as lina will then be. how old are the girls now
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Question 397790: mila is 7 years older than her sister lina. in 3 years,she will be 17 years more than one-fifth as old as lina will then be. how old are the girls now Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! Let M = Mila's present age
Let L = Lina's present age
:
Write an equation for each statement:
:
"mila is 7 years older than her sister lina."
M = L + 7
:
" in 3 years, she will be 17 years more than one-fifth as old as lina will then be."
M + 3 = (L+3) + 17
:
Multiply both sides by 5
5(M+3) = L + 3 + 5(17)
5M + 15 = L + 3 + 85
5M = L + 88 - 15
5M = L + 73
Replace M with (L+7)
5(L + 7) = L + 73
5L + 35 = L + 73
5L - L = 73 - 35
4L = 38
L =
L = 9.5 yrs is Lina's age
then
9.5 + 7 = 16.5 yrs is Mila's age
:
Usually the solution to these problems are integers, maybe there is a mistake
in the problem. Anyway, this is the method to use.
:
:
We can confirm our solutions in the statement:
"in 3 years,she will be 17 years more than one-fifth as old as lina:
16.5 + 3 = (9.5+3) + 17
19.5 = *12.5 + 17
19.5 = 2.5 + 17
