Answer:

Explanations:
According to the question, the average adult heart pumps about 84 mL/s of blood at 72 bpm. This can be expressed in equation form as:
84mL = 1 second ....................... 1
In order to calculate how long it would take the average heart to circulate 3400 mL of blood, this can be expressed as;
3400mL = x ..................................... 2
where;
x is the time it would take the average heart to circulate 3400 mL of blood.
Divide both equations 1 and 2 to set up the proportion equation;

Cross multiply the resulting proportion to get "x"

Note that 72 beats per minute will not enter into the equation