Solving differential equations backward in time

I have a system of differential equations with specail boundary conditions:

diff(S(t), t) = -K(t)*S(t)/N, diff(K(t), t) = K(t)*S(t)/N, where S(0)=10, K(T)=20; I would like to solve this system in forward and backward in time. Is it posible to solve in the dsolve command ? or are there another command to this system ?

Thanks,

Answer 1

[madhan ravi]

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