word problem *

[tamiatha]

Yoshi is 12 years older than his sister. 6 years from now, the sum of their ages will be 32. Find Yoshi's present age.
yoshi age = 12 + sister's age
yoshi = y
siser = x
y = 12 + x
12 + x + x +6 = 32
18 + 2x = 14
x = 7
what did i do wrong
7 canot be the correct answer
it is not a logical answer
it is also not one of the choices on my answer sheet

 

[Mrspi]

Re: word problem

Yoshi is 12 years older than his sister. 6 years from now, the sum of their ages will be 32. Find Yoshi's present age.
yoshi age = 12 + sister's age
yoshi = y
siser = x
y = 12 + x
12 + x + x +6 = 32<-----This equation is incorrect...see my comments below
18 + 2x = 14<-----where did THIS equation come from?
x = 7<----how did you get x = 7 from the equation 18 + 2x = 14???
what did i do wrong
7 canot be the correct answer<----probably not, since it came from using incorrect algebra on an equation that was incorrect to begin with
it is not a logical answer<----Why do you think 7 is not logical?
it is also not one of the choices on my answer sheet<---ok, that's probably a good hint that there's something wrong with your work

If y = Yoshi's age NOW, how old will yoshi be in 6 years?
In 6 years, Yoshi's age will be y + 6

If x = sister's age NOW, then in 6 years, the sister's age will be x + 6

We know this....in 6 years, the sum of Yoshi's age and his sister's age will be 32 years. So....

y + 6 + x + 6 = 32
y + x + 12 = 32
y + x = 20

So, the two equations in your system should be

y = x + 12
y + x = 20

Try solving this system and see if you get a "better" solution.