1. Work problems
#22:
An experienced bricklayer constructs a small wall in 3 hours. The apprentice (you) completes the job in 6 hours.
Find how long it takes if they work together.
The answer is not 4.5 hours (no averaging!)
The answer is not 9 hours (Makes no sense!!)

2. Make a chart! Equation set-up: 1/3 + 1/6 = 1/x Solution: x = 2 hrs
An experienced bricklayer constructs a small wall in 3 hours. The apprentice (you) completes the job in 6 hours. Find how long it takes if they work together.
Make a chart!
Equation set-up:
1/3 + 1/6 = 1/x
Solution: x = 2 hrs
Hours to complete total job
Part of job completed in 1 hr
Experienced worker 3
1/3
You 6
1/6
Team effort x
1/x

3. #21 Section 5.6
Smith Engineering found that an experienced surveyor surveys a roadbed in 4 hours. An apprentice surveyor needs 5 hours to do the job. If the two work together, find how long it takes them to complete the job?
Set-up: LCD = 20x
1/4 + 1/5 = 1/x Solution x = 20/9 hours
How long to finish the job
Portion of the job completed in 1 hr.
Co-worker
4 hrs
Apprentice
5 hrs
1/5
Team or working together X
1/x

4. #26: Distance = Rate X Time
A boat can travel 9 miles upstream in the same amount of time it takes to travel 11 miles downstream. If the current of the river is 3 mi/hr, complete the chart below and use it to find the speed of the boat in still water.

5. A boat can travel 9 miles upstream in the same amount of time it takes to travel 11 miles downstream. If the current of the river is 3 mi/hr, complete the chart below and use it to find the speed of the boat in still water (let boat speed = x). Dist = rate x time  time = Dist/rate
Distance
Rate (boat & river)
Time
Upstream (against river current – slows you down)
9 mi
X - 3
(Same time)
Downstream (with river current – speeds you up)
11 mi
X + 3
Set-up:
9(x+3) = 11 (x-3)
9x+27 = 11x-33
= 11x – 9x
= 2x
= x
The speed of the boat in still water is 30 mi/hr