Nathan usually drinks 31 ounces of water per day. He read that he should drink 59 ounces of water per day. If he starts drinking 59 ounces, what is the percent increase? Round to the nearest percent.

You have to know the difference in change, so you do 59-31 and you get 28, then since you want to know the change in percent you divide the difference, which is 28 and divide that by 31, which is the original amount consumed, and you get 28/31, and you get. 90 which is 90%