Posted by vanessa on Sunday, January 10, 2010 at 2:07pm.
Share $100 between Joseph and Peter so that Joseph has 3 times as much as Peter.

simple equations ( math)  Marth, Sunday, January 10, 2010 at 2:17pm
Let x = the amount of money that Peter has. Now try to set up the equation to solve for x.

simple equations ( math)  vanessa, Sunday, January 10, 2010 at 2:20pm
sorry i don't understand

simple equations ( math)  Marth, Sunday, January 10, 2010 at 2:23pm
You want to solve for the amount of money that Peter has. So you let your variable equal that amount of money.
Now, you know that Peter's money + Joseph's money = $100.
Can you express the amount of money Joseph has in terms of x, the amount of money Peter has? 
simple equations ( math)  vanessa, Sunday, January 10, 2010 at 2:27pm
so altogether the have $100. Joseph has 3 time more then Peter. would joseph have $75 and Peter have $15 ?

simple equations ( math)  Marth, Sunday, January 10, 2010 at 2:28pm
I believe you mean that Peter has $25, which would be correct.
Could you write the equation you used to solve that? 
simple equations ( math)  vanessa, Sunday, January 10, 2010 at 2:30pm
ohyes sorry i meant that.
3/4 of 100 is 75
so the rest is 25 
simple equations ( math)  Marth, Sunday, January 10, 2010 at 2:35pm
Again, where is your variable (x) in the equation?
You should have an equation that looks like the following:
"Peter's money + Joseph's money = $100"
x + J(x) = $100
where J(x) is a (simple) function expressing Joseph's money in terms of x.
The reason I ask is not to make it hard now, but because you will encounter problems that cannot be solved mentally  multiple variable problems, for example. You will need to be able to set up an equation from the word problem. 
simple equations ( math)  vanessa, Sunday, January 10, 2010 at 2:38pm
Oh. ook ... thank you for your help

simple equations ( math)  wendy, Tuesday, November 27, 2012 at 10:26pm
alex spent 3/7 of his money. he give 1/4 of the reminder to his sister. he had $120
left. how much money did he have in the begining