John is 5 years older than Mary. In 10 years, twice John's age decreased by Mary's age is 35, and John's age will be twice Mary's current age. Find their ages now.
If x is Mary's age now and y is John's age now, which system of equations could not be used to solve the problem?

1. y = x + 5 and y + 10 = 2x
2. y = x + 5 and 2(y + 10)-(x + 10) = 35
3. y = x + 5 and 2(y + 10) = x

Question

John is 5 years older than Mary. In 10 years, twice John's age decreased by Mary's age is 35, and John's age will be twice Mary's current age. Find their ages now.
If x is Mary's age now and y is John's age now, which system of equations could not be used to solve the problem?

1. y = x + 5 and y + 10 = 2x
2. y = x + 5 and 2(y + 10)-(x + 10) = 35
3. y = x + 5 and 2(y + 10) = x

anonymous · Answer

Wow that is wordy. But I believe it's (3) that can't be used. 
(2) can be used because it's just a direct mathematical symbol of the wording of the problem, and (1) is correct because y+10=2x means that in 10 years, so "y" is John's current age plus 10 years, John's age then will be twice Mary's, and Mary's current age is x now so twice that is 2x, so that makes sense.
As for (3), it says y+10 so John's current age, y, plus 10 years and then 2 times all of that gives Mary's current age. That's not correct. The 2 should be on the right side with the x because in 10 years' time John will be twice Mary's age. Mary won't be twice John's age as (3) states so that one is incorrect.

I think. I'm pretty sure.

anonymous · Answer

thank you very much :)

anonymous · Answer

You're welcome! :) No one's a fan of these kind of wordy age problems :P

anonymous · Answer

haha i noticed no one answered for a really long time lol

anonymous · Answer

Yeah I considered skipping over it too haha :P but all the other posts were already being answered so I was cornered ;) Hope you don't have any more of these kinds!

anonymous · Answer

i don't lol