Word Problem.

[Surfer]

So I already have the format laid out, it's just from there I don't know where to go.

Peanuts cost $0.80 a pound, cashews $1.50 a pound, and walnuts $1.50 a pound. A store clerk needs to make six pounds of mixed nuts using these three types so the total cost is $6.90. If she wants to use 3 times as much peanuts as cashews, find out how much each type she should use.

So this is what I have:
X = Peanuts (0.80)
Y = Cashews (1.50)
Z = Walnuts (1.50)

So I have: .80X + 1.50Y + 1.50Z = 6.90

Do I have to add anything to that or is that the right formula to begin with? I figured I can also add:
X = 3 + Y into that equation but I'm not too sure.

I also have a second one, quite simple but I want to see if it's right:

The Sum of three numbers is 235. One number is 10 more than the second number, and the third number is three times the second number. Find the numbers.

I have A + B+ C = 235

A = 10 + B
C = 3B

Is that right, if so do I plug them in. Because when I do it doesn't seem to get to the answer.

Thanks in advance.

 

[stapel]

It might help to note that X = 3Y, and that X + Y + Z = 6. With this information, you can write the relationship in terms of only one variable.

Eliz.

 

[Surfer]

Sweet. That was quick.

I meant to put it as 3Y. And I'm assuming that the 6 is in regards to the total pounds? Not the price?

 

[Gene]

Yes, the 6 is pounds

(Just one hint. Next time you assign variables consider P, C, & W instead of X, Y & Z. That keeps the kind of nut tied to the variable.)

I have A + B+ C = 235
A = 10 + B
C = 3B
Looks good that far. If you want your work looked at you gotta show it, but those equations should do it.

 

[Surfer]

Ok, I have the first one figured out. I'm just going to post my work in case someone else might want this.

3C + C + W = 6
4C + W = 6
4(1) + 2 = 6
6 = 6 C = 1, W = 2
P = 3C => P = 3(1) => P = 3

So:
.80(3) + 1.50(1) + 1.50(2) = 6.90
6.90 = 6.90
Thanks for the clarifications.

 

[Denis]

The Sum of three numbers is 235. One number is 10 more than the second number, and the third number is three times the second number. Find the numbers.
I have A + B+ C = 235
A = 10 + B
C = 3B
Is that right, if so do I plug them in. Because when I do it doesn't seem to get to the answer.

Keep it simple:
let x = 2nd number ; then 1st number = x+10 and 3rd number = 2x
so: x+10 + x + 2x = 235
OK?