Explain how you can use boyle's law to determine the new volume of gas when its pressure is increased from 270 kpa to 540 kpa? the original volume of gas was 1 l. assume the temperature and number of particles are constant. what is the new volume?

There are several information's already given in the question. Based on the information's the answer can be easily deduced. 

We know the formula

P1*V1/T1 = P2*V2/T2

As the temperature is constant, so T1 and T2 can be negated. The formula changes to 
P1*V1 = P2*V2
70 * 1 = 540 * V2
270/540 = V2
V2 = 0.5

From the above deduction, we can conclude that the new volume is 0.5 liters. I hope that the procedure is clear enough for you to understand.

I’m not sure what your trying to say here.. can you clarify again?

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 .