Answer:
A
Step-by-step explanation:
Choosing 4 men from seven can be done in 7C4 = 35 ways
(There are 7 to choose from then 6 and 5 and 4 = 7 x 6 x 5 x 4
but we don’t want them in order so we need to divide by 4! = 4 x 3 x 2 x 1)
Similarly choosing 4 women from 11 can be done in 11C4 = 330 ways.
Total number of ways to choose 4 men and 4 women = 35 x 330 = 11550
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
Answer:
0.631
Step-by-step explanation:
