Because there is no record of all things. As we have partially unknow information, it can never be held as a fact.
Answer:
As Per Given Information
20x objective lens was used by specimen
10x ocular lens was also used by him.
we have to find the total magnification.
For calculating the total magnification we 'll simply do multiplication
Total Magnification = 20x × 10x
Total Magnification = 200x
So , the total magnification will be 200x .
