The change in value over 5 years is expected to be
$55,000 - 4,300 = 50,700
Since this change in value is spread over 5 years, the amount of depreciation recorded for each full year will be
$50,700/5 = $10,140
The period from July 1 to December 31 is 6 months or 1/2 year, so the depreciation recorded the first year will be 1/2 the above amount:
(1/2)*$10,140 = $5,070