Answer:
500 lb
Step-by-step explanation:
Let x lb be the weight of seawater needed to get 17.5 lb of salt.
Now,
x lb - 100%
17.5 lb - 3.5%
Write a proportion:

Cross multiply:

Obviously, 0.8, all you do is move over the decimal.
Answer:
10.7 m
Step-by-step explanation:
Given that,
The speed of a sound wave, v = 6,420 m/s
The frequency of the wave, f = 600 Hz
We need to find the wavelength of the wave. We can find it using the below relation as follows :

So, the wavelength of the sound wave is equal to 10.7 m.
The answer is D. Since the x line is seconds and y is feet traveled it would mean that the train travels 180 feet in 3 seconds