Answer:
209 : 40 or 5.225 : 1
Step-by-step explanation:
Your calculator can tell you the ratio 8.36/1.60 is 5.225. Writing that decimal as a fraction, you can factor out 25 to get ...
8.36 : 1.6 = 5.225 : 1 = 5225 : 1000 = (25)(209) : (25)(40) = 209 : 40
Answer:
Redskins cost $0.25 and golden roughs cost $0.35.
Step-by-step explanation:
Let r be the cost of a redskin and g the cost of golden roughs. So we have the system of equations:
r + 4g = 1.65
2r + 3g = 1.55
Multiply the first equation by -2:
-2r - 8g = -3.30
Adding this to the second equation:
-5g = -1.75
g = 0.35.
Now substitute this into the first equation:
r + 4*0.35 = 1.65
r = 1.65 - 1.40
r = 0.25.
This problem can be solve by graphing (technology), as suggested.
The answer is posted as an attached image. We see that after about 14.75 years, the invading species will surpass the indigenous population.
If it needs to be solved mathematically and accurately, the math is a little more advanced, using the bisection method, or Newton's method.
However, we can also do that by trial and error, starting from 14.75. It is easier than you might think.
Post if you would like to have more information on one or the other methods.
Note: the scale of y has been shrunk by 1000, so each unit on the y-axis represents 1000 frogs.