Question

15 is 0.4% of what number?

Answer 1

0.06 is 0.4% of 15
just look up percentage calculator <span />

Answer 2

 0.4 is 100% - because it's the output value of the task. If 0.4 is 100%, so wyou can write it down as 0.4=100%. We know, that x is 15% of the output value, so we can write it down as x=15%. so your anser is 15