anonymous 4 years ago Four years ago, Jane was twice as old as Sam. Four years on from now, Sam will be 3/4 of Jane's age. How old is Jane now?

1. anonymous

2. anonymous

ok now that i got that out of my system, lets see if we can do it.

3. Akshay_Budhkar

LOL @satellite's attachement

4. anonymous

Let J denote Jane's current age, and S Sam's current age (J - 4) = 2(S - 4) (J + 4) = 3/4 (S + 4) Solve the system for J.

5. anonymous

K thanks

6. anonymous

I think I got it wrong... I think the second equation should be 3/4 (J + 4) = (S + 4)

7. anonymous

looks good to me. i was trying something that i thought might be simpler but it was more complicated

8. anonymous

i will write it anyway, and see if it makes sense

9. anonymous

Yep I was definitely wrong in my first post. It should be J - 4 = 2(s - 4) 3/4 (J + 4) = S + 4 In which case you should get J=12, S=8

10. anonymous

as per marine, $J-4=2(S-4)$ $J-4=2S-8$ $J=2S-4$ is one equation. the next one is $\frac{3}{4}(J+4)=S+4$ $\frac{3}{4}J+3=S+4$ $\frac{3}{4}J-1=S$ now we can substitute $J=\frac{3}{4}J-1$ for S in the first equation and get $J=2\times \frac{3}{4}(J-1)-4$ $J=\frac{3}{2}J-6$ $6=\frac{1}{2}J$ $J = 12$