An unknown element is found to have 3 isotopes. Given the information below, calculate the average atomic mass of the element. Round your answer to 2 places behind the decimal.

elements make up everything, and they combine to make compounds.

the answer is c

answer;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds