30% just means 30/100 which can be simplified to 3/10. In order to find the number of hits you just need to multiple .3 by the total attempts, being 240, which comes out as 76.
For the second question, your first option is correct, you would rewrite 8 in power-base form 8=2^3 as the first step to solving the equation, power base form is exponential form.
