Help, please

**camstill** · October 26th 2008, 07:27 PM

The Volume, V of a given mass of gas varies directly as the temperature

3
T and inversely as the pressure, P. If V= 276.0in when T= 230 degrees

2 2
and P= 10 lbs , what is the volume when T= 130 degrees and P = 15 lbs ?

3
The answer is 104.0 in Please show work so I can understand.

Thanks

**camstill** · October 26th 2008, 07:33 PM

the squares and cubes didn't come out right

I'll repost

**Rafael Almeida** · October 26th 2008, 07:44 PM

In math lang:

$V \propto \frac{T}{P}$

Let $V_1 = 276.0$ . In the transition, temperature goes from 230 to 130. So, new temperature is $\frac{13}{23}$ of original temperature. Pressure goes from 10 to 15, and the new pressure is $\frac{3}{2}$ of the original.

Since V is directly proportional to T and inversely proportional to P, it will suffer a $1 - \frac{13}{23} \simeq 43\%$ decrease because of temperature drop and a $1 - \frac{2}{3}$ decrease because pressure P raises 50%. So,

$V_2 = \frac{13}{23}\frac{2}{3}V_1 = \frac{13 \times 2 \times 276 }{23 \times 3} = 104.0$

Hope it's clear,

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