Remember the formulas switch depending what you're looking for. (Remember one formula and you can find the rest by using algebra to get the other formulas). The formulas are on page 77. Questions 5 each problem states find the percentage. You are looking for percentage. It looks a little confusing because you see the 15% but actually you are trying to find the percentage of the problem. So, 15% is actually the rate and 930 is the base. Plug in your numbers to the formula P = R x B.
For the next section; it wants rates so the formula is R = P / B. So what % (rate) = P / B. Plug your other numbers into the formula. 5 is actually 500% but you would move the decimal before starting your division so it is 5; assume the numbers shown are already converted from a percentage because they don't have the % sign.
For the next section: it wants the base. So, the formula is B = P / R. Again, plug your numbers into the formula. Hope this helps.