1) May: 248$ and june 265$. The difference is 17$ and then you divide the difference with the old price: 17/ 248 = 6,85%
2) Same method, the difference is 59$ so 27,44%'
3) The difference is 9,5$ so you answer is 63,3%
4) The difference is 10$ divided by the original price: 10/24 = 41,66%