This is driving me nuts, please explain rate of return. I thought that i knew it but nope..... for some reason for the life of me I cant seem to get the right answer. I am using the BA II Plus

1. What rate of return results in a present value of $432 for $250 received one year from now and another $250 received two years from now?

BOOK ANSWER: 10.94%

I keep on getting the answer of 10.32%

2. What rate of return results in a present value of $23 for $25 received one year from now?

BOOK ANSWER: 8.4%

For this question, it keeps on giving me 8.69%, but when reversing the question and placing 8.4% as interest, my payment comes out to be 24.94 or something like

My main concern is that I don't understand how the book is getting these answers, and it seems that the publisher is incorrect.