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:
The length of s is 5.1 inches to the nearest tenth of an inch
Step-by-step explanation:
In Δ RST
∵ t is the opposite side to ∠T
∵ r is the opposite side to ∠R
∵ s is the opposite side to ∠S
→ To find s let us use the cosine rule
∴ s² = t² + r² - 2 × t × r × cos∠S
∵ t = 4.1 inches, r = 7.1 inches, and m∠S = 45°
→ Substitute them in the rule above
∴ s² = (4.1)² + (7.1)² - 2 × 4.1 × 7.1 × cos(45°)
∴ s² = 16.81 + 50.41 - 41.1677568
∴ s² = 26.0522432
→ Take √ for both sides
∴ s = 5.10413981
→ Round it to the nearest tenth
∴ s = 5.1 inches
∴ The length of s is 5.1 inches to the nearest tenth of an inch
