easy algebra word problem. pleeeease help.

[Cassandra123]

Three years ago Jeff was three times as old as Mary was and half as old as Lara was. Three years from now Jeff will be twice as old as Mary will be. how old are Jeff, Mary, and Lara?

gahhh math :/

ive even tried guess and check but i cannot get it.

please show work so i can understand how you got it please?

please and thank you!

 

[Deleted member 4993]

Three years ago Jeff was three times as old as Mary was and half as old as Lara was. Three years from now Jeff will be twice as old as Mary will be. how old are Jeff, Mary, and Lara?

gahhh math :/

ive even tried guess and check but i cannot get it.

please show work so i can understand how you got it please?

please and thank you!

Assume

Jeff' s age NOW = J

Mary's age NOW = M

Lara's age NOW = L

Three years ago

Jeff' s age = J - 3

Mary's age = M - 3

Lara's age = L - 3

Jeff was three times as old as Mary was ? (J-3) = 3 * (M-3) ......................................(1)

Jeff was half as old as Lara was ? (J-3) = 1/2* (L-3)................................................(2)

Three years from now

Jeff' s age = J + 3

Mary's age = M + 3

Lara's age = L + 3

Jeff will be twice as old as Mary will be? (J+3) = 2 * (M+3).........................................(3)

3 equations and 3 uknowns - solve it.

 

[mmm4444bot]

tried guess and check

Did that give you a headache ?

You are asked for three unknown numbers. Did you pick symbols, to represent these numbers? That's usually the first step.

J = Jeff's current age

M = Mary's current age

L = Lara's current age

We need to get an equation that contains only one of these symbols, so we examine the given information, looking for relationships between the numbers J, M, and L.

So, let's write some relationships.

"Three years ago Jeff was"

We express Jeff's age three years in the past, by subtracting 3 from his current age, yes?

In other words, Jeff's age three years ago is expressed as (J - 3).

Now, continuing with the first sentence:

Three years ago Jeff was three times as old as Mary

Of course, Mary's age three years ago is expressed as (M - 3). Since Jeff was three times older than Mary, at that point in time, Jeff was older, yes?

I mean, since he's the older one, we need to multiply Mary's age by 3, to get it equal to Jeff's age (at that time).

(J - 3) = 3(M - 3)

Does that make sense?

Can you write an equation that represents the following part of the first sentence?

Three years ago Jeff was half as old as Lara was.

Continuing with the second sentence:

Three years from now, Jeff will be twice as old as Mary.

Write an equation that represents the relationship in this statement, too. You should realize how to express the future age of Jeff and Mary, when they're each three years older than they currently are.

Then, please show me your "system of equations".

 

[Cassandra123]

ok so it woudl be

THREE YEARS AGO

(J-3)=3(M-3)

(J-3)=1/2(L-3) or 2(J-3)=(M-3)


THREE YEARS FROM NOW

(J+3)=2(M=3)


one question, when they said three years from now do they mean from three years ago when Jeff was three times as old, 6 years later is the "three years from now" do you understand what im confused about?

 

[mmm4444bot]

When they say "three years from now" they mean three years from now, not three years from three years ago.

If they wanted to say three years from three years ago, they would have said somehing like, "three years from then".

That's the difference between then and now.