Simple Algebra

• Aug 16th 2009, 03:19 AM
fvaras89
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
• Aug 16th 2009, 03:23 AM
e^(i*pi)
Quote:

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

$\displaystyle J = M - 7$

At t=4

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

You can set these two equations equal and solve for M. From there use the first equation to find J
• Aug 16th 2009, 03:30 AM
fvaras89
i really dont know what to do after, im sorry could u help me out abit more if it doesnt bother u?
• Aug 16th 2009, 03:40 AM
e^(i*pi)
$\displaystyle J = \frac{M-6}{2}$

$\displaystyle J = M - 7$

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

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

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

$\displaystyle J = 8-7 = 1$