Algebra Demystified 2nd Ed

(Marvins-Underground-K-12) #1
Chapter 8 linear appliCaTionS 277

The equation to solve is 401   +  201 = ^1 t. The LCD is 40t.


1
40

1
20

1

40 1
40

1
20

40 1

40 1
40

+=

+







= 







t
tt
t
t 


+ 





=

+=
=
==

40 1
20

40

240
340
40
3

(^1313)
t
tt
t
t
Together Robert and Paul can assemble the bookcase in 1331 minutes or
13 minutes 20 seconds.



  1. Worker Quantity Rate Time


Pipe I 1 67
1
76 =^67

7/6

Pipe II 1 1/t t
Together 1 43
1
34 43

/

/ =

3/4

The equation to solve is^6
7


+ ^1 = ^4
3
t

. The LCD is 21t.
6
7


14
3
21 6
7

1 21 4
3
21 6
7

2

+=
 +





= 










+

t
t
t

t

t 11 1 28

18 21 28
18 18
21 10
21
10

t
t

t

tt
tt
t
t







=

+=
−−
=

=

Alone, Pipe II can fill the reservoir in^2101 hours or 2 hours 6 minutes.^
( 101 of an hour is 101 of 60 minutes and 101 ⋅ 60  =  6 .)

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