Sales=c(840,1470,2110,4000,7590,10950,10530,9470,7790,5890)

Sales ~ M*(((P+Q)^2/P)*exp(-(P+Q)*T79))/(1+(Q/P)*exp(-(P+Q)*T79))^2 

Bpdf=m*((p+q)^2/p)*exp(-(p+q)*T2)/(1+(q/p)*exp(-(p+q)*T2))^2
Bcdf=m*(1-exp(-(p+q)*T2))/(1+(q/p)*exp(-(p+q)*T2))