So first create and define your variables:
Z = amount of zebra fish
N = amount of neon tetras
Now create your equations:
2z+2.15n=31.20
z+n=15
This is your system. There are multiple methods to use but in this problem I’ll use the substitution method by simplifying the bottom equation.
2z+2.15n=31.20
z=15-n
Now I’ll plug the bottom equation into the top one.
2(15-n)+2.15n=31.20
And just solve from here.
30-2n+2.15n=31.20
0.15n=1.20
n=8
So he bout 8 neon tetras, and 15-8= 7, so he bought 7 zebra fish
Pi/3 is in the first quadrant, and all trigonometric functions are positive in the first quadrant,
Therefore, cos pi/3 is positive.
Answer: D) 10 jerseys
Step-by-step explanation:
Let j represent the number of jerseys and C for total cost
Local company eqn: C = 5.25j + 45
Online company eqn: C = 7.75j + 20
Set both sides equal to solve:
5.25j + 45 = 7.75j + 20
5.25j - 7.75j = 20 -45
- 2.5j = -25

j = 10
Therefore, the cost is the same for both companies when 10 jerseys are sold
A, since n=20 and p=5% if children are vaccinated mean number of new infections =np= 20*0.05=1 p(x<=2) = P(x=0)+P(x=1)