On December 31, 2005, Artificial Oil Company’s unproved property account for leases that are not individually significant had a balance of \($800,000.\) The impairment allowance account had a balance of \($75,000.\) Give the entries for each of the following transactions occurring in 2005, 2006, and 2007. (All transactions concern insignificant unproved leases.)

a. Assuming Artificial has a policy of maintaining a 55% allowance, i.e., 55% of gross unproved properties, give the entry to record impairment on December 31, 2005.

b. During 2006, Artificial surrendered leases that cost \($300,000.\)

c. During 2006, leases that cost \($50,000\) were proved.

d. During 2006, leases costing \($310,000\) were acquired.

e. Give the entry to record impairment on December 31, 2006.

f. During 2007, leases costing \($428,000\) were surrendered.