Don’t need algebra. Need a brain. The answer is the remainder of the difference between the 2 (.10)divided equally (.05).
I liked your thinking. But there is a first element to the equation that will help others see how you arrived at the answer. Specifically, the use of the word ‘more’ implies that one should first remove that one dollar to ascertain the price of the price of the ball in the remainder. After doing that your equal difference result gives you the price of the ball.