Algebra Demystified 2nd Ed

226 algebra De mystif ieD 54 increased by 21.3% is 54 + (0.213)(54) = 54 + 11.502 = 65.502 128 decreased by 8.16% is 128 – (0.0 ...

Chapter 8 linear appliCaTionS 227 The data used in the following examples and practice problems can be found in the 129th editio ...

228 algebra De mystif ieD Let x = 1st class price on January 1, 1995 $0.44 is 37.5% more than this quantity. 0440375 0441 0 375 ...

Chapter 8 linear appliCaTionS 229 ✔SOLUTIONS $75 will be increased by 15%: 75 + (0.15)(75) = 75 + 11.25 = 86.25 The new rate wi ...

230 algebra De mystif ieD The original amount is increased by 25%. Let x represent the original amount. xx xx x x x += += += = ...

Chapter 8 linear appliCaTionS 231 Let x represent the wholesale price. 40% of the wholesale price is 0.40x. The retail price is ...

232 algebra De mystif ieD PRACTICE 2 is what percent of 5? 5 is what percent of 2? 3 is what percent of 15? 15 is what percent ...

Chapter 8 linear appliCaTionS 233 18 18 18 18 18 10 1810 180 18 10 1000 () .() % x x x x = = = === 18 is 1000% of 1.8. 2 1 4 ...

234 algebra De mystif ieD EXAMPLE The cost formula for a manufacturer’s product is C = 5000 + 2x, where C is the cost (in dollar ...

Chapter 8 linear appliCaTionS 235 We begin by substituting numbers given in the problem for variables in the formula. (a) If 12, ...

236 algebra De mystif ieD We begin by substituting numbers given in the question for variables in the formula. (a) The height is ...

Chapter 8 linear appliCaTionS 237 If degrees Fahrenheit and degrees Celsius are the same, then we begin with F = C. We can repla ...

238 algebra De mystif ieD The volume of a box with a rectangular bottom is given by V = 120h, where V is the volume in cubic in ...

Chapter 8 linear appliCaTionS 239 The salary is $410, so S = 200 + 0.10s becomes 410 = 200 + 0.10s. 410 200 010 200 200 210 01 ...

240 algebra De mystif ieD The LCD is 9. 9 5 9 32 92 95 9 32     −     =         − ()() ( FF F )) () = −= ...

Chapter 8 linear appliCaTionS 241 Number Sense Many problems require us to use “common sense” to solve them—that is, basic mathe ...

242 algebra De mystif ieD PRACTICE Find two consecutive numbers whose sum is 57. Find three consecutive numbers whose sum is 48 ...

Chapter 8 linear appliCaTionS 243 Let x = first number, x + 1 = second number, x + 2 = third number, and x + 3 = fourth number. ...

244 algebra De mystif ieD number is eight more than this, so x + 8 represents the other number. Their sum is 70, giving us x + ( ...

Chapter 8 linear appliCaTionS 245 ✔SOLUTIONS Let x = first number, and x + 15 = second number. Their sum is 85, so x + (x + 15) ...