Algebra Demystified 2nd Ed

400 algebra De mystif ieD

x () ()()( )

()

= ––^60 ± ^60 – ^41224 =^ ± 

21

−^2603600 –– 

=  ± =  ±  = 

896

2

60 2704

2

60 52

2

(^)  , 45  6
(x = 56 is not likely to be a solution—the price would be $152!) If the price
of the shoes are 40 + 2(4) = $48 per pair, the revenue will be $3648.

More Work Problems

You might recall from Chapter 8 that we can solve work problems by filling in

the table below with information given in the problem. In the work formula

Q = rt (Q = quantity, r = rate, and t = time), Q is usually “1.” We then solve the

equation: Worker 1’s Rate + Worker 2’s Rate = Together Rate.

The information given in the problem is usually the time one or both work-

ers need to complete the job. We want the rates not the times. We can solve for

r in Q = rt to get the rates.

Q = rt

Q

t

=r

Because Q is usually “1,”^1

t

=r.

The equation to solve is usually:

111

Worker1’s time Worker2’s time Togetherti

+=

mme

Worker Quantity Rate Time

Worker 1 (^1) Worker s^11 , time
Worker 1’s time
Worker 2 1 1
Worker 2,s time
Worker 2’s time
Together (^1) Together^1 time^ Together time