Simplify: 7·(a+5)–30 =
1 answer:
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Answer:
Step-by-step explanation:
Amount of brine = 100 gal
amount of salt = 80 lb
rate of water running = 4 gal / min
Let A be the amount of salt in lb in the tank at any time t.
(a) dA/dt = rate of salt in - rate of salt out
Rate of salt in = 0
rate of salt out = A x 4 / 100 = A / 25 lb/min
So, dA/dt = 0 - A/25 = - A/25 lb/min
When t = 0, A = 80 lb
So,
(b) Now, A = 40 lb
So,
take log on both the sides
t = 17.3 minutes
Answer:
(2) (100, 300)
Step-by-step explanation:
One wave can be divided on 4 parts, as show on the picture.
Since a length of one whole wave equals 400, a length of each part is nanometers.
The height of the wave is decreasing on the second and on the third part, hence over the interval (100, 300).
