1200 because the difference of 8100 and 6900 is 1200.
Answer:
The number is 
Step-by-step explanation:
If something is 30% of a whole it means that if whe divide the whole into 100 and take 30, you will get this number. In order to get the whole we need to divide it my the 40 by
and so we get.....
40 ÷
= 