working backward

[tostarz]

kelby has some money. she bought a birthday gift for $15 and spent one-half of the ramaining money for clothes. she spent 4/5 on gas and used 1/5 of what was left on entrainment. She the saved $24 that she had left. how much money di she have to start with?

I am not sure if I am doing this right. this is what I have so far t-15=t
1/2t=t
4/5t=t
1/5t=t
money left =24
1/5t+24=t
-1/5t -1/5t
24=t-1/5t

or should I have done this
1/5t+24=t
5/1 -5/1
t+24=t-5/1
-t+24=t-5/1-t
24=

or should it be
t-1/5=24
which would make t=29

 

[Ishuda]

kelby has some money. she bought a birthday gift for $15 and spent one-half of the ramaining money for clothes. she spent 4/5 on gas and used 1/5 of what was left on entrainment. She the saved $24 that she had left. how much money di she have to start with?

I am not sure if I am doing this right. this is what I have so far t-15=t
1/2t=t
4/5t=t
1/5t=t
money left =24
1/5t+24=t
-1/5t -1/5t
24=t-1/5t

or should I have done this
1/5t+24=t
5/1 -5/1
t+24=t-5/1
-t+24=t-5/1-t
24=

or should it be
t-1/5=24
which would make t=29

What I do with problems like this is write down three thing for each happening and that is (1) the happening, (2) the amount spent, and (3) the amount left. So let's start at the

[FONT=courier new]beginning,     0,                  t
birthday gift, 15,                 [t - 15]
clothes,       (1/2)[t-15],        [(1/2)(t-15)]
gas.           (4/5)[(1/2)(t-15)], [(1/5)(1/2)(t-15)]
...[/FONT]

can you go on from there?

 

[tostarz]

thanks

thanks