Mystery number: the number is less than 19 and greater than 18.
5000 more than the number has 187000 thousands.
200 less than the number has 4 hundreds.

The answer to it is    
180, 000 <n> 190, 000 
180,000 + 2000 = n = 5000-187, 000 
182,000 = n = 182, 000   
Or,  
 180, 000 <n> 190,000                     
 n + 5000= 187, 000                           n – 2000 = 180, 000 
 n= 187, 000- 5000                             n = 180, 000 + 2000 
 n= 182, 000                                       n= 182, 000 

Iam thinking the answer is a.) knew