SOLUTION: A carpenter orders 84 doors. He orders 3 times as many red doors as blue doors. How many blue doors does he order?

Question 1066348: A carpenter orders 84 doors. He orders 3 times as many red doors as blue doors. How many blue doors does he order?
Found 2 solutions by josmiceli, MathTherapy:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
[ blue doors ] / [ red doors ] = 1/3
Let = number of blue doors
= number of red doors
--------------------------------

Multiply both sides by

and

---------------------
He orders 21 blue doors
----------------------
check:

Divide top and bottom of the left
side by

OK
Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

A carpenter orders 84 doors. He orders 3 times as many red doors as blue doors. How many blue doors does he order?

Let number of blue doors be B
Then number of red doors = 3B
We then get: B + 3B = 84
4B = 84
B, or number of blue doors =
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