Instead of doing this problem for you,  I'll do one exactly like it
with different numbers.  Use it as a guide to solve yours:

When a number is decreased by 51% (of x), the result is 45. 
------------- --------------- ----------  ------------- --
      |              |            |             |        |
      x              -          0.51x           =       45 

Put it together:

      x - 0.51x = 45

What is the original number to the nearest tenth

  1.00x - 0.51x = 45
          0.49x = 45
              x = 45/0.49
              x = 91.8

Now do yours exactly step-by-step the same way.
              
Edwin