Answer: The % digestibility of the sugar alternative is 10.
Step-by-step explanation:
First we have to know how many grams of the sugar replacement were in the total rat feces. We know 22,5% of the feces were the sugar replacement, so we use cross multiplication for that:
If 20 grams is 100% of the feces, then
x grams / 22.5% = 20grams / 100%
xgrams = (22.5 . 20grams) / 100% = 4.5grams
If each rat ingested 1gram of the sugar replacement, all five rats ate a total of 5grams.
Now we have to check how much of this sugar replacement was digested. If the rats ate 5grams and 4.5grams were present in their feces
5grams - 4.5grams = 0.5grams
This means they digested 0.5grams.
We use cross multiplication again to find out which percentage of the initial sugar replacement this represents.
If 5grams is 100% of the ingested sugar replacement, then
x% / 0.5grams = 100% / 5grams
x% = (0.5grams . 100%) / 5grams = 10%