1 point 50. Zinc does show variable
valency like d-block elements
because : *
O a) It is a metal
O b) It is low melting
c) Two melting are present in
outermost orbit
O d) d - orbital is complete.​

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