SOLUTION: Erin's age is 3 times Warren's. In 4 years she will be twice as old as he will be. How old is each now? so far I have {E+4 = 2(w x 3 + 4)}

Algebra ->  Expressions-with-variables -> SOLUTION: Erin's age is 3 times Warren's. In 4 years she will be twice as old as he will be. How old is each now? so far I have {E+4 = 2(w x 3 + 4)}      Log On


   



Question 253286: Erin's age is 3 times Warren's. In 4 years she will be twice as old as he will be. How old is each now?
so far I have {E+4 = 2(w x 3 + 4)}

Found 3 solutions by Greenfinch, josmiceli, richwmiller:
Answer by Greenfinch(383) About Me  (Show Source):
You can put this solution on YOUR website!
Warren's age is X, so Erin's age is 3X
In 4 years Warren is x+4, Erin is 3X+4
We are told 3X+4 = 2(X+4)
so 3X+4 = 2X + 8
so X = 4
Warren is 4, Erin is 12
in 4 years Warren is 8, Erin is 16
The trick is to use Warren's age to express Erin's age

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
You have the right idea
let e = Erin's age now
Let w = Warren's age now
given:
e+=+3w
In 4 years Erin's age will be e+%2B+4
In 4 years Warren's age will be w+%2B+4
e+%2B+4+=+2%2A%28w+%2B+4%29
-------------------
Substituting:
3w+%2B+4+=+2%2A%28w+%2B+4%29
3w+%2B+4+=+2w+%2B+8
w+=+4
and, since
e+=+3w
e+=+3%2A4
e+=+12
Erin is 12 and Warren is 4
Notice that in 4 years, Erin will be twice Warren's age
12+%2B+4+=+2%2A%284+%2B+4%29

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!

You should be making two equations with two unknowns.
You substituted 3w for w instead of 3w for e
Don't use x for multiplication sign
Use the asterisk above the number 8
Also we usually put numbers before letters
3w not w3
w3 can be confused for w^3
Mathematics is a language and has rules just like English and Spanish
and it has its own vocabulary and word order.
e=3w
(e+4)=2(w+4)
substitute 3w for e
3w+4=2w+8
subtract 2w from both sides
subtract 4 from both sides
w=4
e=3*w=12
check
12+4=2(4+4)
16=2*8
16=16