How did calculus professor dr. rate refer to his family members

Dr. Rate refers to his family members as the “related rates.” This question is actually an old calculus riddle. In differential calculus, problems regarding related rates include looking for a rate at which a certain quantity changes by relating that quantity to others which have known rates of change. 

when in a crucial situation, after calling 911, the correct posture for delivering effective compression is the proper hand placement.

first, place two fingers at the sternum, then put the heel of your other hand next to the fingers and place hand on top of the other. lock your elbows by using your body’s weight and compress the victim’s chest with a depth of 2 inches.

moreover, do 15 compression and 2 breaths, this process must be done four times until there is a pulse or a arrive.