Since when it is hibernating it beats 10 times per minute and that is 20 % of the normal volume we can use a rule of 3 to find his normal herat rate. If 10 times per minutes is 20% of its normal volume then x times per minutes is 100%. So we have:
To find the heart hate of a grizzly bear when not hibernating, we need to get the heart rate when hibernating (10 beats per minute) and make it equal to 20% in a rule of three, where we want to know the 100% value (normal heart beat rate):
