Question

Jack is twice as old as Lillian. Six years ago Jack was five times as old as Lillian was then. How old is Lillian now?
@whpalmer4 @phi @e.mccormick

Answer 1

Jack is twice as old as Lillian
J = 2L

Six years ago Jack was five times as old as Lillian was then
J-6 = 5(L-6)

solve for L

Answer 2

Can you help me solve for L? So far i have only got up to:
J-6=5L-30

Answer 3

since J = 2L, replace J with 2L in the equation above

Answer 4

2L-6=5L-30 ?

Answer 5

@sourwing

Answer 6

Yes, that's right, solve for L to get Lillian's current age.

Answer 7

But how can i solve for L? i need help on that.

Answer 8

\[2L - 6 = 5L - 30\]You want to get L alone on one side of the equals sign, and a number on the other. You can do whatever you want, as long as you do it to both sides of the equation. You might start by adding 6 to both sides, for example:
\[2L - 6 + 6 = 5L - 30 + 6\]\[2L = 5L -24\]Any ideas?

Answer 9

How did u get 24? understood that you subtracted 30-6=24 but why subtract?

Answer 10

No, I didn't subtract, I added -30 + 6

But here, let's do it a different way:

\[2L - 6 = 5L - 30\]Let's add 30 to both sides:
\[2L - 6 + 30 = 5L - 30 + 30\]\[2L - 6 + 30 = 5L\]Comfortable with that?

Answer 11

yes
\[2L-24=5L\]
now what do i do?

Answer 12

No, -6 + 30 = 30 - 6 =

Answer 13

it's okay. now i got the problem.

Answer 14

thanks