Step-by-step explanation:
the median just identifies the value, where half of the other values are smaller, and the other half of the other values are bigger.
in the original set this is 990.
by changing 1085 to 995 this value still stays on the bigger side of 990, so the median is still 990 and unchanged.
the mean changes.
the mean is the sum of all values divided by the number of values.
originally it was
(755+855+970+985+990+1010+1020+1060+1085)/9 = 970
now it is
(755+855+970+985+990+995+1010+1020+1060)/9 = 960
it decreased by 10.