Converting units of time
Susan has 96 minutes to complete a test at school. The test begins at 1:59 PM. And Susan has volleyball practice at 4:00 PM. How much time will Susan have between the end of the test and the beginning of volleyball practice? Let's think about this a little bit. So the test begins at 1:59. So it's a very strange time to begin a test, but let's just go with that. So let me draw a little time line here. So let's say that this is 2 o'clock PM. Then we're going to have 3:00 PM. Then we're going to have 4 o'clock PM, which is also when volleyball practice begins. So this is volleyball practice. It's going to start then and then go on from 4:00 PM. And then the test begins at 1:59. So let me continue the number line. So this right over here is 1:00 PM. So the test is going to begin at 1:59, so 1 minute before 2 PM. We know that there are 60 minutes in an hour. So 1:59 is 1 minute before 2:00 PM. So I'm not drawing it completely it scale, but this right over here is 1:59 PM. So we use 1 minute to get to 2:00 PM. And then, let's see, we have to get up to 96 minutes. So then you get another 60 minutes to go to 3:00 PM. So, so far, we've used a cumulative 61. So this is 1 minute. So this is how long the test has been going on since the beginning. So 1 minute by 2:00 PM, 61 minutes by 3:00 PM. If we go all the way to 4:00 PM, that's going to be another 60. That'd be 121 minutes, which is longer than the actual test. So we know that the entire test is 96 minutes. So we're going to get to some point right over here, some point like this. That's 96 minutes. And what we need to figure out is, is what is left over? What is this distance right over here? Or what is this time, this difference in time right over here? And so to figure that out, we had to figure out the time at which 96 minutes have passed since the beginning of the exam. So at 3 o'clock, 61 minutes have passed. And so if we, if we say well how many more minutes have to go on for the end of the test? It's going to be 96 minus 61. So the amount of time that elapses past 3 minutes is 96 minus 61, which is 35 minutes. So this right over here is going to be 3:35. And so now our question is, how much time is there between 3:35 and 4:00 PM? Well, once again, 60 minutes in an hour. 4:00 PM is essentially the 60th minute. So if we take 60 minus 35, we get 2:25. So she has a total of 25 minutes remaining after the test before she has to get to volleyball practice. Just as a review. One minute between 1:59 and 2:00, then another 60. That gets us to 61 total minutes. Then another 35 minutes gets us to 96 minutes have passed. And that also gets us to 3:35, which means we have 25 minutes until 4:00.