1. 8.1 Work Solving Work Problems

2. 8.1 Solving Work Problems The term “Work” implies that something is getting done. This something can be mowing a lawn, washing windows, filling a bathtub with water, and an almost endless list (you can certainly think of others). Here is the setup: t + t = 1 5 3 A sample problem will look like this: Jerry can mow a lawn in 5 hours and Joe can mow the same lawn in 3 hours. How long will the job take if they work together? t/Jerry’s time + t/Joe’s time = 1 Job

3. 8.1 Solving Work Problems Here’s how to solve… t + t = 1 5 3 3t+ 5t = 3*5 Now just solve… 8t = 15 t = 15 8 t = 1.875 1.875 is a perfectly good answer, but in real life is meaningless. We need to convert the answer to actual time. Here’s how…

4. 8.1 Solving Work Problems How to covert decimals to time: Our answer is 1.875. How many hours and minutes is this?.875 x 60 52.5 minutes Yeah! All you have to do is multiply the decimal part by 60 and you’ve got your minutes. (round to the nearest whole number.) Time is not a base 10 system; it is a base 60 system (there are 60 minutes in an hour and 60 seconds in a minute). Creating time out of decimals is easy… 1.875 is two numbers: 1 Hours and (.875)(60) Minutes The answer is 1 hour and 53 minutes (round the minutes)

5. 8.1 Solving Work Problems Let’s try one more: It takes Sally 2 hours to do the dishes. It takes Mary 5 hours to do the dishes (yes, she is very slow). How much time would it take if they worked together? Setup: t + t = 1 2 5 5t + 2t = 2*5 7t = 10 t = 10 7 t = 1.428571 t = 1 hour, 26 minutes How did we get minutes?

6. 8.1 Solving Work Problems That’s all there is to 8.1. Do your homework and check your answers. When done, take your quiz and go on to 8.2 Mixture.