Answer:
Average speed = 9.91 m/s
Explanation :
Total distance covered by a runner = 200 m
Time taken to complete this distance = 20.19 sec
We need to find the average of runner speed in meter/sec
We use the speed, distance, time formula

speed = 
Average speed = 9.91 m/s
that's the final answer.
I hope it will help you.
C. The 2 in the denominator turns into -2 and you just take the coefficients directly from the numerator.
–2x + 4y = –7 . . . . . (1)
y = -1/2x + 5 . . . . . . (2)
Putting (2) into (1), we have:
-2x + 4(-1/2x + 5) = -7
-2x - 2x + 5 = -7
-4x = -7 - 5 = -12
x = -12/-4 = 3
y = -1/2(3) + 5 = -3/2 + 5 = 7/2
Hence, the system has one solution.