1. The problem statement, all variables and given/known data I have worked out the transfer function of a block diagram in 1st order form To = (K/1+ts) and the 2nd part of the question asks to calculate the time for the output temperature to change by 80% when k1=1, k2=2, k3=3 and k4=4 2. Relevant equations where K = (k1k2)/(k1k2k4+k2k3) and t= 1/(k1k2k4+k2k3) 3. The attempt at a solution So K = 0.2 and t = 0.1 and i thought that the equation to do this would be y=K(1-e^(-T/t)) giving 0.8=0.2(1-e^(-T/0.1)) but this doesnt work can anyone see where im going wrong? Is the y=K(1-e^(-T/t)) right? Thanks!