SOLUTION: I can figure out the answer to the problem Anna is 18, Dennis is 9 and Curtis is 5.. but what the teacher wants is to "Define a variable, and then write an equation for each probl

Question 348158: I can figure out the answer to the problem Anna is 18, Dennis is 9 and Curtis is 5.. but what the teacher wants is to "Define a variable, and then write an equation for each problem".
The problem is Anna is twice as old as her brother Dennis, who is 4 years older thean their brother Curtis. The sum of their ages is 32. How old is Anna?
Need to define a variable and then write an equation and not sure how to do that?

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
The problem is Anna is twice as old as her brother Dennis, who is 4 years older
than their brother Curtis.
The sum of their ages is 32. How old is Anna?
:
let a = Anna's age
let d = Dennis's age
let c = Curtis's age
:
Write an equation for each statement, we will try to get everything in terms of d:
:
"Anna is twice as old as her brother Dennis"
a = 2d
:
"who is 4 years older than their brother Curtis."
d = c + 4
Subtract 4 from both sides, and we have
c = d-4
:
" The sum of their ages is 32."
a + d + c = 32
:
Replace a with 2d, and replace c with (d-4)
2d + d + (d-4) = 32
2d + d + d = 32 + 4
4d = 36
d =
d = 9 yrs is Denni's age
then
a = 2(9) = 18 is Anna's age

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