Step-by-step explanation: If there are 45 problem and she can do them in 30 minutes, then you divide 45 by 30 to see how many problems she can do in one minute. 45 problems/30 minutes = 1.5 problems per minute. Then, you multiply 1.5 by 4, because you need to see the 4 minute mark, and 1.5 x 4 = 6. So, your answer is 6 problems.
