Edward's cake recipe calls for 15 3/4 cups of flour and
10 1/2 cups of sugar. it makes enough to serve 100
people. how much flour and sugar will he need to
serve 25 people?

Cups of flour=15  3/4=15+ 3/4=(4*15+3)/4=63/4
Cups of sugar=10  1/2=(2*10+1)/2=21/2

We solve this problem by rule of 3:

63/4 cups of flour100 people
x 25 people

x=(63/4 cups of flout * 25 people)/100 people=1575/400 cups of  flour=
=63/16=(3*16+15)/16=3  15/16  cups of flour.

21/2 cups of sugar100 people
x25 people

x=(21/2 cups fo sugar * 25 people) / 100 people=525/200 cups of sugar= 21/8 =(2*8+ 5)/8=2   5/8 cups of sugar.

 3  15/16  cups of flour and 2  5/8 cups of sugar.