In writing numerical numbers, you should identify the three-letter groupings. The first three-letter grouping would be the hundreds, followed by thousands, by millions, by billions, by trillions, and so on and so forth. In this case, we highest would be billions. So, in word form, that would be: three billion, one hundred fifty two million, three hundred eight thousand and seven hundred twenty six.
The best way to find your answer is to divide 193 by 400 to get .4825 and to make sure if it is the answer you take 400 and multiply .4825 and it will be 193 so .4825 = 48.25%