Today’s Date: 11/15/11 “Work” Word Problems Notes on Handout

“Work” Equation Together + Together = 1 Alone Alone Always “together Over alone + together Over alone” Always equals 1

Ex 1) Nora needs 3 hours to chop down the tree in front of her house. Her younger brother needs 6 hours to do the same job. How much time would it take them if they worked together? Nora’s Part of Job Bro’s Part of Job 1 Whole Job Completed += (2)(1) (6) Multiply every term to get the common denominator

Example 1 cont… a)Define variable: b)Write the equation: c)Solve: x is time together 2 hours (to complete the job together)

T.O.O. SET-UP #3 Do NOT finish the problem. This time they give Sean’s time & time together, but not Ian’s time.

Example 2 (#4 on WS) An inlet pipe can fill a tank in 3 hours. It takes 11 hours for the drainpipe to empty the tank. How long will it take to fill the tank if both the inlet pipe and the drainpipe are open? = Inlet and Drain pipe are working against each other. So, make Drain pipe’s rate alone negative. 1

Example 2 cont… (11)(3) (33)

Example 3 (#5 on WS) Crane A can unload the container ship in 10 hours, and crane B can unload it in 14 hours. Crane A started to unload the ship at noon and was joined by crane B at 2 pm. At what time was the unloading job of the ship completed? Crane A: Started at noon (12:00) Crane B: Started at 2:00 Let x = Crane B’s time Crane A worked 2 hours more than Crane B : x + 2

Example 3 cont… Once you get x, you need to add that time to 2:00 to get “WHAT TIME” job was finished. Finish for HW. Your answer will be a decimal so round to the nearest tenth and convert to “Time”

T.O.O. Work with a neighbor to set up #6. Do NOT finish the problem. Clue: Larger Pump’s time is x – 7

Homework #8 Finish “Work” Problems side of WS a) Define Variable b) Write equation c) Solve Products & Quotients; Sums & Differences side: do Every Other Odd (1, 5, 9, 13, 17, 21)