A gas tank contains 3 gases (N2, O2, CO2). The total pressure of the gases is 825 mmHg. If the pressure of CO2 in 125 mmHg and the pressure of O2 is 350 mmHg, what is the partial pressure of N2 gas?

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .