Substitution Word Problems

Hello...I am working on systems of equations using substitution...I have no problem with regular problems but I have no idea how to set up a word problem...My algebra teacher taught me to just create the equation instead of using a table like the book does. I dont need a answer to my problem I just need to know how to set up this problem. Please help its due tomorrow and I am totally stuck...

The future teachers of America Club at the high school is making a healthy trail mix to sell to students during lunch.The mix will have three times the pounds of raisins as sunflower seeds. Seeds cost $4/ lb. Raisins cost $1.50/ lb. If the group has 34.00 to spend on the raisins and sunflower seeds, how many pounds of each should they buy?

Im just having trouble making the equations...I just don't know what to put with what. Any help?

Rule #1 - Name stuff. Generally, name what is asked.

"how many pounds of each should they buy?"

R = lbs of Raisins
S = lbs of Sunflower Seeds

THAT may be 1/2 the battle. Once you have these clear definitions in your head and on your paper, the rest is translation and a little algebra.

"The mix will have three times the pounds of raisins as sunflower seeds."

R = 3*S

Stare at that until you see it is a proper translation.

"Seeds cost $4/ lb. Raisins cost $1.50/ lb. If the group has 34.00 to spend on the raisins and sunflower seeds, "

($4/ lb)*R + ($1.50/ lb)*S = $34.00

Stare at that until you see it is a proper translation.

Can you take it from there? Since you indicated that you could do "regular" problems, I'd have to call this one a freebie. Let's see you do one from the beginning.