Well, then I'm guessing you're only feeding 90 of them since 10 of the dogs are sleeping. If so, then set up a proportion:
\(\frac{number of dogs}{amount of food}\)
\(\frac{100}{10.3}\)
A proportion is a two fractions set equal to eachother. So, the second fraction will be the number of dogs over x. X will be the amount of food the dogs will get.
\(\frac{90}{x}\)
Set the two equations equal to eachother
\(\frac{100}{10.3} = \frac{90}{x}\)
To solve a proportion, cross multiply
100 x X = 100x
90 x 10.3 = 927
100x = 927
Divide 100
x = 9.27
So, the dogs will receive 9.27 of food
