Engineering Economic Analysis

96 MORE INTERESTFORMULAS

!SOlUTION 2

30

t. t 2;

0-1-2-3-4

1 1

P F

The relationship betweenPandFin the diagram is

P= F(PjF, 15%,4)

Next we compute the future sums of the three payments, as follows:

30

t t t

F=0-1-2-3-4 + 0-1-2-3-4 + 0-1-2-3-4

t t 2t

F =FI+F2+ 20

- 20(Fj P,15%,2) +30(Fj P,15%,1) + 20

Combining the two equations, we have

P= [FI + F2+20](P j F,15%,4)

=[20(Fj P,15%,2) +30(Fj P,15%, 1) +20](P j F,15%,4)

= 20(1.322) + 30(1.150) + 20

=$46.28

:..f;..'~.'.'.._ ",."_",,,"~~"-'_"..',_H"'_' ,:, ,.- ~

...SOlUJ}Q~[3. ='

30

Y t Y

0-1-2-3-4

~ ~

P PI

30

Y t Y Y Y Y ~

1-2-3-4 =1-2-3-4 + 1-2-3-4

tt ~ =

PI

P=PI (PjF, 15%, 1) PI=20(P j A,15%,3) + lO(Pj F,15%,2)

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