The cost of two jackets and three shirts was sh 1800.After the cost of a jacket was increased by 20%,the cost of two jackets and two shirts was 4800.Calculate the new cost of each.

Let x have probability generating function gx (s) and let un generating function u(s) of the sequence uo, u1, satisfies p(x > n). show that the (1- s)u(s) = 1 - gx(s), whenever the series defining these generating functions converge.