Help me! and how to get the answer!!

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Which region represents the solution to the given system of inequalities? |-0.5x+y23 | 1.5x+ys-1 5 4 -3 -2 -1 1 2 3 4