Answer:
43
Step-by-step explanation:
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 flour--------------100 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 sugar-----------------100 people
x-----------------------------------------25 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.
Answer: 3 15/16 cups of flour and 2 5/8 cups of sugar.
we are supposed to explain
Which situation could be solved using the equation 
As we can see in the given equation , one number is -4 and the other number is 4
When we add two number of same value but opposite in sign we get zero.
This equivalent to the real life situation of paying a post paid bills.
Suppose you are using a post paid service , and the bills gets generated at the end of the month.
Suppose the bills amount is $x.
Once you pay that bills , then total outstanding again becomes $0.
Because 
The first one is b. The second one is d. Sorry if I’m wrong :(
By pascal triangle this second term should be
5s^4v<span />