Question 248874
V = k*T/P where:


V = volume
T = temperature
P = pressure
k = constant of variation.


When:


V = 231 cm^3
T = 42 degrees
P = 20kg/cm^2,


The formula becomes:


231 = k*42/20


Solve for k to get:


k = 110


The constant of variation is equal to 110.


When T = 30 and P = 15 and k = 110, the formula becomes:


V =  30*110/15 = 220 cm^3


Here's a <a href = "http://www.regentsprep.org/Regents/math/algtrig/ATE7/Inverse%20Variation.htm" target = "_blank">reference</a> that explains how the variation formulas work.