SOLUTION: If a varies directly as b, a=20, when b=4, find a when b=a

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Question 987580: If a varies directly as b, a=20, when b=4, find a when b=a
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
A varies directly as b. Let the constant of variability be K. So
a+=+Kb
20+=+K%2A4
5+=+K
Our equation is a+=+5b
You are asked for a value of b that results in a=b. I am not sure if that means find a when b=20 or find the value where a is equal to b.
The only way a=b is when b=0
If b = 20, the a=100