Question 423454
The question is When a number is decreased by 40% of itself is 306. What is the number? 
I sovled the equation by letting x = the number 
Then put 40% in decimal form .40
Sovle the equation x-.40=306
                     -.40=-.40
                   x= 665 
but the answer is 510. 
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x - 0.4x = 306
Solve that one.
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I don't see how you got 665.  Maybe you meant 765, if you divided by 0.4 ?