Last year Angela used her 60% margin account and purchased 100 shares of stock at a price of $33 a share. Today she sold this stock for $36 a share. Angela paid a total of $70 in margin interest for the year. Ignoring transaction costs, what rate of return did Angela earn on this investment?

To find the rate of return on Angela's investment, we need to calculate the total cost and the total selling price of the shares.

Step 1: Calculate the total cost of the shares:
Angela purchased 100 shares at a price of $33 per share.
Total cost = Number of shares * Price per share
Total cost = 100 * $33 = $3300

Step 2: Calculate the total selling price of the shares:
Angela sold 100 shares at a price of $36 per share.
Total selling price = Number of shares * Selling price per share
Total selling price = 100 * $36 = $3600

Step 3: Calculate the profit made from the investment:
Profit = Total selling price - Total cost
Profit = $3600 - $3300 = $300

Step 4: Calculate the rate of return:
Rate of return = (Profit / Total cost) * 100
Rate of return = ($300 / $3300) * 100 = 9.09%

Therefore, Angela earned a rate of return of 9.09% on this investment.