Intro to rates
- [Instructor] We're told that Nierria earns $75 for 4 hours of tutoring. How much does Nierria earn for 1 hour of tutoring? Pause this video, and see if you can figure that out. Well, the key here is $75 for 4 hours of tutoring. And there's a couple of ways you can think about it. The ratio here is $75 for every 4 hours. So if you wanted one hour of tutoring, well, it's just going to be 1/4 of the $75, or you could just take 75 and divide by 4. Another way you could think about it, you could say Nierria gets $75 for every 4 hours, which is another way of saying that Nierria is going to earn 75 divided by 4 dollars per hour. So really we just have to figure out what 75 divided by 4 is. So let's do a little bit of long division. So 4 goes into 7 one time, 1 times 4 is 4. We're going to subtract. 7 minus 4 is 3. Bring down that 5. 4 goes into 35 eight times. 8 times 4 is 32. I will subtract again. I get a 3. Well now I'm going to get some decimals here, so let me bring down a zero. 4 goes into 30 seven times. 7 times 4 is 28. Subtract, and then I get a 2. Bring down another zero. 4 goes into 20 five times. 5 times 4 is 20, and I am done, no more remainder here. So we get that Nierria earns 18.75 dollars, dollars per hour, or you can just say that she makes $18.75 per hour.