A bicycle pump contains air at STP. As the tire is pumped up, the volume of air decreases by 30% with each stroke. What is the new pressure of air (in atm) in the chamber after the first stroke, assuming no temperature change? Select the correct answer. a. 1.4 b. 0.7 c. 2.6 d. 0.9 e. 2 What I have done is T1=T2 P1*V1/(R*n1)=P2*V2/(R*n2) P1*V1/(n1)=P2*V2/(n2) But the question doesn't tell us number of mole of the air, how do we solve this question?