Georgia is working on a math test with 75 problems on it. After 20 minutes she has completed 10 problems. After another 20 minutes, she has completed twice as many problems. She has 40 minutes to complete the rest of the test. How many problems does she have left to solve? Let's answer step by step:
Georgia's test started with 75 problems and then Georgia completed 10, 75 - 10 = 65 problems. After 20 minutes she completes twice as many problems, 10 x 2 = 20. With 40 minutes left she has completed 10 + 20 problems = 30 problems. From the original 75 problems she has solved 30, 75 - 30 = 45 problems she has left. The answer: 45.