a=出厂含税价。
非增值部分= a / 1.17,增值部分=(a/1.17) x 0.17, 退税= (a / 1.17) x 0.13
100 + 20 = a + [(a/1.17)x0.13] - (a/1.17) x 0.17
120 = a + a x 0.1111 - a x 0.145
120 = 0.9661 a
a = 124.21
124.21/ 6.16 = 20.16 usd.
验证:
20.16 / 1.17 = 17.23 不含税价
17.23 X 0.17 = 2.93 增值税
17.23 X 0.13 = 2.24 退税
20.23 + 2.24 - 2.93 = 19.54
19.54 X 6.16 = 120.36 = 100 + 20.
改正:
从倒数第二行:
20.16 + 2.24-2.93 = 19.47
19.47 x 6.16 = 119.94 约等于 120 = 100 +20[收起]