Amanda purchased a 30 year $10,000 bond at par value with a 4% coupon.
We find the coupon amount each year
Coupon amount = actual amount of bond * 4%
= 10,000 * 0.04 = 400
Coupon amount for every year = 400
Total value of coupons for 30 years = 400 * 30 = 12000
$12,000 is the total value of the coupons