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?
y=x+ 5 and y+ 10 = 2x
y=x+5 and 2ly + + 10) = 35
y=x+5 and 2(y + 10) = x
Option 2 is correct that could be used to solve the problem.
Present age of Mary is x
And present age of John is y
Since, john is 5 years older than Mary hence, we get
In 10 years twice john's age is decreased by Mary's age by 35
hence, Option 2 is correct which could be use to solve the problem.
3. y = x+5 and 2(y +10) = x
The variables are defined in the problem statement. The second equation, 2(y+10)=x, says, in effect, ...
... In 10 years, twice John's age will equal Mary's age now.
There is no corresponding statement in the given problem, so this equation is useless for finding the solution.
The solution to the last system of equations is (x, y) = (-30, -25)—not a viable solution to any age problem.
5 to the 3 power is 15 so add and subtract 10
answer: john is 20, mary is 15
So number 2. is the correct answer...
Use the value of j=m+5 in the second equation to get:
m=15, and j=m+5=20
So Mary is currently 15 years old and John is 20 years old.