To determine the number of platelets present in the human body, we need a relation that would relate this value to the given value above which is the number of white blood cells. Fortunately, we are given a ratio of 30. So, we use this value as follows:
number of platelets/number of white blood cells = 30
number of platelets / 8×10^3 white blood cells = 30
number of platelets = 240000
