Answer:
speed = distance/time
Step-by-step explanation:
The faster a sound wave travels, the more distance it will cover in the same period of time. If a sound wave were observed to travel a distance of 700 meters in 2 seconds, then the speed of the wave would be 350 m/s.
Let's set up a proportion.

Then solve for x:
12 x 800 = 9600
9600/100 = 96
96 is 12% of the 800 students. :)
Hope this helped! If you have anymore questions or don't understand, please comment or DM me. :)
20,27,34
The common difference is 7
Parallel lines, slope is the same so
1) 3x+8y = 12
8y = -3x + 12
y = -3/8(x) + 3/2, slope = -3/8
slope of a line that is parallel = -3/8
2)5x+4y = 5
4y = -5x + 5
y = -5/4(x) + 5/4; slope is -5/4
slope of a line that is parallel = -5/4
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perpendicular, slope is opposite and reciprocal
3)
3x+8y = 11
8y = -3x + 11
y = -3/8(x) + 11/8. slope = -3/8
slope of perpendicular line = 8/3
4)
x = -7, slope is undefined
so slope of perpendicular line is 0
5)
3x+2y = 12
2y = -3x + 12
y = -3/2(x) + 6 ; slope = -3/2
5x - 6y = 8
6y = 4x - 8
y = 2/3(x) - 4/3; slope is 2/3
slope is opposite and reciprocal, so the equals are perpendicular
6)
3x + y = 5
y = -3x + 5; slope = -3
6x + 2y = -15
2y = -6x - 15
y = -3x - 7.5; slope = -3
both have slope = -3 so equations are parallel
81,149, 274.... adding three numbers from the last would help you
like if you take 7 = 4 + 2 +1
or 13 = 7 + 4 +2
similarly 44+24+13 = 81
81+44 +24 = 149
149 + 81 +44 = 274
hope you get it!