# Math Help - Simple Algebra

1. ## Simple Algebra

Hello im new to this site.. and was wondering if anyone could help me with this question..

Jennifer is 7 years younger than melisa. In 4 years time Jennifer will be 1 year older than half of Melisas age at that time. How old are Jennifer and Melissa now?

I'd like to see all working out including simultaneous equation.. im very confused.. thank you

2. Originally Posted by fvaras89
Hello im new to this site.. and was wondering if anyone could help me with this question..

Jennifer is 7 years younger than melisa. In 4 years time Jennifer will be 1 year older than half of Melisas age at that time. How old are Jennifer and Melissa now?

I'd like to see all working out including simultaneous equation.. im very confused.. thank you
Let M be Melissa's age, J be Jennifer's age

At t=0

$J = M - 7$

At t=4

$J+4 +1 = \frac{M+4}{2} \rightarrow J = \frac{M-6}{2}$

You can set these two equations equal and solve for M. From there use the first equation to find J

3. i really dont know what to do after, im sorry could u help me out abit more if it doesnt bother u?

4. $J = \frac{M-6}{2}$

$J = M - 7$

These two must be equal so we can say that $M-7 = \frac{M-6}{2}$. Then solve for M

$2M-14 = M-6 \: \rightarrow \: M = 8$

Now M is known use J= M-7 to find J:

$J = 8-7 = 1$