A 12% coupon rate per year implies a coupon of $6 on each of these dates. If we want to compute the accrued interest as of April 30, we will have to determine the actual number of days between April 30 and the last coupon date, i.e., March 1. We have 60 days (= 30 + 30, in March and April, respectively).

The reference period, March 1 to September 1, has 184 actual days.

Thus,

$\text{Accrued interest} = \frac{60}{184} \times 6 = 1.9565$