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

Answer 1

j=m+5, 2(j+10)-(m+10)=35 

So number 2. is the correct answer...

Use the value of j=m+5 in the second equation to get:

2(m+5+10)-m-10=35

2m+30-m-10=35

m+20=35

m=15, and j=m+5=20

So Mary is currently 15 years old and John is 20 years old.

Answer 2

Answer:

Option 2 is correct that could be used to solve the problem.

Step-by-step explanation:

Present age of Mary is x

And present age of John is y  

Since, john is 5 years older than Mary hence, we get

y=x+5

In 10 years twice john's age is decreased by Mary's age by 35

2(y+10)-(x+10)=35

hence, Option 2 is correct which could be use to solve the problem.