Value of x when not rounded is somewhere

between 0 and 1.

We know that

J can have a

value of 0.1 to 0.9 because x is

rounded to tenth.

But we are also required to find

J-K when it is maximum we need to make sure that J is maximum so J can

only be 0.9

Coming to K, K can have a value such as

0.abc where a,b and c are placeholders. Because J is rounded to thousandth.

But we should make sure that

K is as small as possible for J-K to be maximum.

How can we round O.abc to O.a such that O.a is 0.9 ?we know that

0.85 is the least number when rounded that gives us 0.9 hence 0.abc can be rewritten as 0.85c

at this point we should make sure that

c is least as well that way K is least hence c = 0

Therefore,

K = 0.850Hence, J-K = 0.9-0.850 = 0.05

option C
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This is my response to the question and may be incorrect. Feel free to rectify any mistakes