0.00042 as a percent have to remember that 1 equal 100% and that what you need to do is just to multiply the number by 100 and add at the end symbol % . 0.00042 * 100 = 0.042% and then you get your answer!
If you can't split up the peanut butter cups, the identical bags would each have 1 chocolate bar and 1 peanut butter cup because 30 cannot be devided between 18 bags as whole numbers more than once.