SOLUTION: the base material for a certain roadbed is 80% crushed rock when measured by weight. How many tons of this material must be mixed with another material containing 30% rock to make
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-> SOLUTION: the base material for a certain roadbed is 80% crushed rock when measured by weight. How many tons of this material must be mixed with another material containing 30% rock to make
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Question 722370: the base material for a certain roadbed is 80% crushed rock when measured by weight. How many tons of this material must be mixed with another material containing 30% rock to make 150 tons of material that is 40% crushed rock? Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Let = tons of 80% crushed rock needed
Let = tons of 30% crushed rock needed
given:
(1)
(2)
---------------------------
(2)
(2)
(2)
--------------------
Multiply both sides of (1) by
and subtract (1) from (2)
(2)
(1)
and, since
(1)
(1)
(1)
30 tons of 80% crushed rock are needed
120 tons of 30% crushed rock are needed
check:
(2)
(2)
(2)
(2)
(2)
OK
