HP 12c Solutions Handbook page 61

Any of the five variables: a) list price, b) discount (as a percentage of list
price), c) manufacturing cost, d) operating expense (as a percentage), e)
net profit after tax (as a percentage) may be calculated if the other four are
known.
Since the tax rage varies from company to company, provision is made for
inputting your applicable tax rate. The example problem uses a tax rate of
48%.
KEYSTROKES
CLEAR
5
6
4
0
0
3
1
2
0
1
00
DISPLAY
00-
01- 45
02- 45
03- 10
04- 45
05- 40
06- 16
07- 45
08- 40
09- 45
10- 10
11-43, 33 00
12- 45
13- 45
14- 45
15- 45
16- 10
17- 16
18-
19- 40
20- 20
21- 31
22- 10
60
5
6
4
0
0
3
1
2
0
1