X - Columbian coffee ( in pounds),
y - Brazilian coffee ( in pounds );
x + y = 100
8.85 x + 3.85 y = 6.55 ( x + y )
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x = 100 - y
8.85 ( 100 - y ) + 3.85 y = 6.55 * 100
855 - 8.55 y + 3.85 y = 655
- 5 y = - 230
y = ( - 230 ) : ( - 5 )
y = 46
x = 100 - 46
x = 54
Answer: 54 pounds of Columbian coffee and 46 pounds of Brazilian coffee should be used.
Answer:
<em>The speed of sound at 20°C is 343.42 m/s.</em>
<em>You have to wait 1.75 seconds to hear the sound of the bat hitting the ball</em>
Step-by-step explanation:
<u>Speed of Sound</u>
The speed of sound is not constant with temperature. Generally speaking, the greater the temperature, the greater the speed of sound.
The approximate speed of sound in dry air at temperatures T near 0°C is calculated from:

The air is at T=20°C, thus the speed of sound is:


The speed of sound at 20°C is 343.42 m/s.
To calculate the time to hear the sound after the batter hits the ball, we use the formula of constant speed motion:

Where d is the distance and t is the time. Solving for t:

Substituting the values v=343.42 m/s and d=600 m:

t = 1.75 s
You have to wait 1.75 seconds to hear the sound of the bat hitting the ball
Well, (m^2-7m-11) ÷ (m-8) = m+1 with a remainder of -3