**Answer:**

a. Accumulated post-retirement benefit obligation at the end of 2013 and 2014 are $6,461.54 and $9,230.77 respectively.

b. Service costs of 2013 and 2014 are $1,615.38 and $1,846.15 respectively.

**Explanation:**

**a. Calculation of accumulated post-retirement benefit obligationat the end of 2013 and 2014**

Attribution period = (55 - 29) = 26 years

Accumulated post-retirement benefit obligation (APRBO) at a year end equal to the expected post-retirement benefit obligation multiply by the division of the number of years he was hired and attribution period. That is,

APRBO at the end of 2013 = $42,000 × (4 ÷ 26) = $6,461.54

APRBO at the end of 2014 = $48,000 × (5 ÷ 26) = $9,230.77

Therefore, accumulated post-retirement benefit obligation (APRBO) at the end of 2013 and 2014 are $6,461.54 and $9,230.77 respectively.

**b. Calculation of the service cost for 2013 and 2014**

Service cost for a particular year is equal to expected post-retirement benefit obligation for the year divided by the attribution period. Therefore, we have:

Service cost of 2013 = 42,000 ÷ 26 = $1,615.38

Service cost of 2014 = 48,000 ÷ 26 = $1,846.15

Therefore, service costs of 2013 and 2014 are $1,615.38 and $1,846.15 respectively.