Ahuman body contains about 2.7 x 10^4 microliters of blood for each pound of body weight. each microliter of blood contains about 7 x 10^4 white blood cells. about how many white blood cells are in the body of a 140-lb person?

Step 1:
Find how many microliters of blood there are in a 140lb person.

=140 * (2.7*10^4)
=140*(2.7*10*10*10*10)
=140*27,000
=3,780,000 # of microliters of blood in a 140lb person

Step 2:
Find how many white blood cells in a 140lb person

=3,780,000* (7*10^4)
=3,780,000*(7*10*10*10*10)
=3,780,000*(70,000)
=264,600,000,000 # of white blood cells in a 140lb person

(or 2.646 * 10^11 using scientific notation)

Hope this helps! :)