Finding Final Value

Sydney is considering making a monthly investment for her son who will be five years old on his next birthday. She wishes to make payments until his 18th birthday and intends to pay £50 per month into an account yielding an APR of 12·68%. She plans to start making payments into the account the month after her son?s fifth birthday.
How much will be in the account immediately after the final payment has been made?
A £18,847 B £18,377 C £17,606 D £18,610

Ans
12 root of 1.1268 = 1.01

50x ((1·01)^(13×12)-1) / 1.01-1
=?18,610