Find the mystery number.

Question

1.  When I add 7 to three times my number I get 43. 
2. When I add 6 to five times my number I get 36.

Answer 1

7 + 3x = 43

3x = 43-7 = 36

x = 36/3 = 12

6 + 5x = 36

5x = 36-6 =30

x =30/5 = 6

you have two different numbers, not the same BUT you have an ambigous "fie" that seems like "five" but maybe you meant to somehow write 2.5, or 2.five

then x=12

6+2.5x = 36

2.5x = 30

x = 30/2.5 = 12