Question

a store is having a sale on walnuts and chocolate chip.s For 3 pounds of walnuts and 2 pounds of chocolate chips. the total cost is $14. for 8 pounds of walnuts and 4 pounds of chocolate chips, the total cost is $33. find the cost for each pound of walnuts and each pound of chocolate chips.

Answer 1

w= walnuts
c= chocolate chips

Set up an equation for each set of #s above:
3w+2c= $14
8w+4c= $33

You have to solve for one variable in equation one, then substitute it in equation two.

3w+2c= 14
Subtract 2c from both sides
3w= 14-2c
Divide both sides by 3
w= (14-2c)/3

Substitute it in equation two.
8w+4c=33
8(14-2c)/3+4c=33
(112-16c)/3+4c=33
Multiply everything by 3 to eliminate the fraction
(3/1)((112-16c)/3)+(3)(4c) = (33)(3)
112-16c+12c=99
112-4c=99
Subtract 112 from both sides
-4c= -13
Divide both sides by -4
c=13/4= $3.25 cost for lb of chocolate chips

Substitute that answer in to the equation:
8w+4c=33
8w+4(3.25)= 33
8w+13=33
Subtract 13 from both sides
8w= 20
Divide both sides by 8
w=20/8= $2.50 cost for lb of walnuts

Check:
3w+2c=14
3(2.50)+2(3.25)=14
7.50+6.50= 14
14=14

Hope this helps!! I'll look at your other problems when I get home.