Answer:
t = [tex]\frac{D-M}{Mr}[/tex]
Step-by-step explanation:
Given
D = M + Mrt ( subtract M from both sides )
D - M = Mrt ( divide both sides by Mr )
[tex]\frac{D-M}{Mr}[/tex] = t
t = D/Mr - 1/r or (D - M)/Mr
D = M + Mrt
isolate t
D - M = Mrt
(D - M)/M = rt
D/M - 1 = rt
D/Mr - 1/r = t
