When I try solving the attached problem, I do not get the same answer in my book which is 0.5580.

Since the problem is at most 20, I have done the following:

0.04(0.96^0 + 0.96^1 + 0.96^2 + 0.96^3 + 0.96^4 + ... + 0.96^19) = 0.535243

Any suggestions in going about this problem would be helpful!