If 9 is subtracted from a certain number and the difference is divided by 3, the result is 1 more than (1/7) of the original number. Find the original number.

Question

Just how to set it up and I do not know. 

Answer 1

Here is the procedure 

Let a certain number be “n”

 

Nine is substracted from a certain number = n - 9

The difference is divided by 3. (n - 9)/3

1 more than 1/7 of the original number (1/7)*n + 1

 

Then:

(n - 9)/3 = (n/7) + 1

 

All you gotta do now is solve for n

(n-9) = (3n/7) + 3

n - 9 - 3 = 3n/7

7*(n-12) = 3n

7n - 84 = 3n

7n - 3n = 84

4n = 84

n = 21