SME
Grade 6 Science · Problem type
Blood pumped each minute
Use this for “70 beats a minute, 70 mL a beat. How much blood a minute?”
Table
Heart rate
(beats per minute)
Blood each minute
(mL)
This is an example. Type your own values to start a new problem.
h
beats
×
b (mL)
=
q (mL)
Formulas
80 × 60 = 4,800
Heart rate × blood per beat = blood each minute
Assumptions
•
Heart rate is how many times the heart beats in one minute. Feel it as your pulse.
•
An adult’s heart pushes out about 70 mL each beat; a sixth grader’s, a little less.
•
At rest an adult’s heart pumps about 5 liters a minute, about all the blood in the body.
•
Exercise raises the heart rate, so the muscles get more oxygen.
Step-by-step
WE KNOW
Heart rate: 80 beats per minute
Blood per beat: 60 mL
FIND
blood each minute
Step 1 · Find blood each minute
80 × 60 = ?
Heart rate × blood per beat = blood each minute
Each beat pushes out the same amount, so multiply by the beats in a minute.
Blood each minute = 4,800 mL (4.8 liters)
Check
Put the numbers back in. Both sides should match.
80 × 60 = 4,800 ✓
Topic check
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