4. For a fully discrete whole life insurance of 10,000 on (45): (i) Bith net and gross premiums are reduced by half starting with the 21st premium. (ii) Expenses are 50% of premium in the first year, 10% of premium in renewal years. (iii) A45 = 0.15, A65 = 0.24, A75 = 0.40 (iv) d= 0.04 (v) 20P45 = 0.90 (vi) 30P45 = 0.75 Calculate the expense reserve at time 30