SOLUTION: A cement manufacturer buys limestone for $3 per pound and a special shale mix for $5 per pound. The two ingredients are mixed into a 100-pound compound that cost $4.25 per pound.

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A cement manufacturer buys limestone for $3 per pound and a special shale mix for $5 per pound. The two ingredients are mixed into a 100-pound compound that cost $4.25 per pound.       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 111944: A cement manufacturer buys limestone for $3 per pound and a special shale mix for $5 per pound. The two ingredients are mixed into a 100-pound compound that cost $4.25 per pound. How much limestone and how much of the shale mix should be added into the compound?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A cement manufacturer buys limestone for $3 per pound and a special shale mix for $5 per pound. The two ingredients are mixed into a 100-pound compound that cost $4.25 per pound. How much limestone and how much of the shale mix should be added into the compound?
:
Let x = amt of limestone
Then
(100-x) = amt of shale
:
3x + 5(100-x) = 4.25(100)
:
3x + 500 - 5x = 425
:
3x - 5x = 425 - 500
:
-2x = -75
:
x = -75/-2
:
x = 37.5 lb of limestone required
and
100 - 37.5 = 62.5 lb of shale