Question

compute 40 percent of 30 percent of 20 percent of 10 percent of 160000

Answer 1

"of" simply means to multiply here.
Also, each percent can be written as a decimal by moving the decimal over two points to the right and removing the % sign.
For example 50% = 0.50 and 15% = 0.15
So, now we have
0.40 x 0.30 x 0.20 x 0.10 x 160000
See if you can multiply this out to find the answer. :)

Answer 2

Does this help at all @lizbeth456 ?