A=P+prtA=P+prtSince tt is on the right side of the equation, switch the sides so it is on the left side of the equation.
P+prt=AP+prt=A
Since PP does not contain the variable to solve for, move it to the right side of the equation by subtracting PP from both sides.prt=−P+Aprt=-P+ADivide each term by prpr and simplify.
t=−Ppr+Apr