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.
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
