annual interest ----- 7,5%
halfyear interest ---- x%
----------------------------------
x = 0,5 *7,5/1 = 3,75%
7,5% +3,5% = 11%
$1500 ---------- 100%
x ----------------- 11%
-----------------------------
X = 11*1500/100 = 165
so this mean that $165 is the simple interest what Kara owes on in a 1,5 year