SOLUTION: Here is the problem I need help with: Carrie is two years less than three times her sister Alicia's age. If the product of their ages is 40, how old is Carrie and how old is Carri

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Question 425826: Here is the problem I need help with: Carrie is two years less than three times her sister Alicia's age. If the product of their ages is 40, how old is Carrie and how old is Carrie and how old is Alicia? so far I have come up with
3a-2=40 which a=14, now I'm stuck and not sure what to do next. Thanks, Dina

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Carrie is two years less than three times her sister Alicia's age.
If the product of their ages is 40, how old is Carrie and how old is Alicia?
:
Let's do it like this:
:
"Carrie is two years less than three times her sister Alicia's age."
c = 3a - 2
:
"If the product of their ages is 40,"
a*c = 40
c = 40%2Fa
:
Replace c in the 1st equation with 40/a
40%2Fa = 3a - 2
multiply both sides by a, results
40 = 3a^2 - 2a
A quadratic equation
3a^2 - 2a - 40 = 0
Factor this to
(3a + 10)(a - 4) = 0
the positive solution is all we want here
a = 4 yrs is Alicia's age
:
Now I know you can find c by yourself. Check your solutions in both original equations