SOLUTION: You are making 10 tons of concrete that is 62% cement by mixing a 20% cement mixture with a 80% cement mixture. a) How much of the 80% cement mixture must you use? Answer in

Question 433560: You are making 10 tons of concrete that is
62% cement by mixing a 20% cement mixture
with a 80% cement mixture.
a) How much of the 80% cement mixture
must you use?
Answer in units of tons.
Help me!
Found 2 solutions by lwsshak3, josmiceli:
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
You are making 10 tons of concrete that is
62% cement by mixing a 20% cement mixture
with a 80% cement mixture.
a) How much of the 80% cement mixture
must you use?
..
let x=tons of 80% mixture to use
then 10-x tons of 20% mixture to use
80%x+20%(10-x)=62%(10)
.8x+2-.2x=6.2
.6x=4.2
x=7 tons
ans:
7 tons of 80% mixture is mixed with 3 tons of the 20% mixture to get 10 tons of 62% concrete.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = tons of 20% mixture to be used
Let = tons of 80% mixture to be used
given:
(1) tons
Tons of concrete in 20% mixture =
Tons of concrete in 80% mixture =
(2)
-------------------------
(2)
(2)
Multiply both sides of (1) by and
subtract (1) from (2)
(2)
(1)

and, since

3 tons of 20% mixture are to be used
7 tons of 80% mixture are to be used
check:
(2)
(2)
(2)

OK
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