twice the sum of 6 and a number is the same as 15 decreased by the number. What is the number ?

Question

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Answer 1

Let a number = n, then twice the sum of 6 and a number = 2(6 + n), and 15 decreased by the number = 15 - n

 

2(6 + n) = 15 - n

 

12 + 2n = 15 - n

 

12 + 3n = 15

 

3n = 3

 

n = 1