The LINDO output in Figure 41 can be used to determine the critical path for Problem. PROBLEM Consider the (simplified) list of activities and predecessors that are involved in building a house...

Immediate

Duration

Activity

Description

Predecessors

(Days)

A

Build foundation

—

5

B

Build walls and ceilings

A

8

C

Build roof

B

10

D

Do electrical wiring

B

5

E

Put in windows

B

4

F

Put on siding

E

6

G

Paint house

C, F

3

FIGURE 41

LINDO Output for Problem 8

MIN

X6 - X1

SUBJECT TO

2) - X1 + X2 >=

5

3) - X2 + X3 >=

8

4) - X3 + X4 >=

4

5) - X3 + X5 >=

10

6) - X4 + X5 >=

6

7)

X6 - X3 >=

5

8)

X6 - X5 >=

3

END

LP OPTIMUM FOUND

AT STEP

6

OBJECTIVE FUNCTION VALUE

1)

26.0000000

VARIABLE

VALUE

REDUCED COST

X6

26.000000

0.000000

X1

0.000000

0.000000

X2

5.000000

0.000000

X3

13.000000

0.000000

X4

17.000000

0.000000

X5

23.000000

0.000000

ROW

SLACK OR SURPLUS

DUAL PRICES

2)

0.000000

-1.000000

3)

0.000000

-1.000000

4)

0.000000

-1.000000

5)

0.000000

0.000000

6)

0.000000

-1.000000

7)

8.000000

0.000000

8)

0.000000

-1.000000

NO. ITERATIONS=

6

RANGES IN WHICH THE BASIS IS UNCHANGED

OBJ COEFFICIENT RANGES

VARIABLE

CURRENT

ALLOWABLE

ALLOWABLE

COEF

INCREASE

DECREASE

X6

1.000000

INFINITY

0.000000

X1

-1.000000

INFINITY

0.000000

X2

0.000000

INFINITY

0.000000

X3

0.000000

INFINITY

0.000000

X4

0.000000

INFINITY

0.000000

X5

0.000000

INFINITY

0.000000

RIGHTHAND SIDE RANGES

ROW

CURRENT

ALLOWABLE

ALLOWABLE

RHS

INCREASE

DECREASE

2

5.000000

INFINITY

5.000000

3

8.000000

INFINITY

13.000000

4

4.000000

0.000000

8.000000

5

10.000000

INFINITY

0.000000

6

6.000000

0.000000

8.000000

7

5.000000

8.000000

INFINITY

8

3.000000

INFINITY

8.000000