The formula for two secants is:
(A+B)*B = (C+D)*D
In the picture :
A = 5
B = 3
C = X
D = 4
(5 +3) * 3 = (X +4)*4
Use distributive property:
24 = 4x + 16
Subtract 16 from both sides:
4x = 8
Divide both sides by 4:
X = 8/4
X = 2
She will use 13 there are four 1/4 per cup 4 times 3 plus 1 =13
Answer: (A)
Packing material is required to fill the box = 
Step-by-step explanation:
The box is shaped like a rectangular prism
base area = 9/10 square foot
height = 1/3 foot
Volume of a prism = base area X Height
=
60/15=4 meaning 25% of the dogs are purebreed