Question

Jack's age next year will be twice Jill's age last year. Their present ages total 45. How old is each now?

Answer 1

Jack's age is \(y\) and Jill's age is \(x\).


"Jack's age next year will be twice Jill's age last year"
How do we write this using our variables?

Answer 2

Here is a hint:
"Jack's age next year"
\(y+1\)
"Jill's age last year"
\(x-1\)

So:
"\(y+1\) will be twice \(x-1\)"

Answer 3

You need to start turning this into an equation first.

Answer 4

We don't want any words to remain.

Answer 5

y-1=2(x-1)

Answer 6

Good. Now how do you write: "Their present ages total 45."

Answer 7

Hint: total means we need to do addition.

Answer 8

y-1=2(x-1)+45

Answer 9

Nope, this is a separate equation. We don't need to worry about the first equation right now.

Answer 10

"Their present ages total 45."

Is a separate equation.

Hint: it will have \(y+x\) in it.