MAT 150 Unit 7

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MAT 150 Unit 7

• Ch 7 4
• Solving Linear Equations with Fractions Decimals

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Section 7 4 Critical Thinking - Work Problems

• Amount of work rate of work X time worked
• A carpenter can install 1 door in 3 hours. How
  many can he install in 30 hours?
• UNKNOWN number of doors installed (amt. of
  work) w
• KNOWN rate of work (as a fraction) 1 door/ 3
  hours
• RELATIONSHIP Amt or work rate X time
• EQUATION w 1/3 (30)
• w 10 doors

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Section 7 4 Critical Thinking - Work Problems

• Working together
• (As amount of work) (Bs amount or work) 1
  completed job
• Pipe 1 fills a tank in 6 min., pipe 2 fills the
  same tank in 8 min. How long does it take for
  both pipes to fill the tank?
• UNKNOWN time (in min.) for both pipes t fill the
  tank t
• KNOWN rate of pipe 1 is 1 tank / 6 minutes, rate
  of pipe 2 is 1 tank/8 minutes.
• RELATIONSHIP 1 job pipe 1 work pipe 2 work

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Section 7 4 Critical Thinking - Work Problems

• EQUATION 1 1 t 1 t
• 6 8
• SOLVE CD 24
• (24) 1 (1 t 1 t) (24)
• 6 8
• 24 4t 3t
• 24 7t
• 24/7 t
• it would take 3 3/7 min to
  fill the tank

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Section 7 4 Critical Thinking - Work Problems

• Working as opposites
• (As amount of work) (Bs amount or work) 1
  completed job
• A faucet fills a tank in 6 min. A drain empties
  it in 8 min. If both the faucet and the drain
  are open how many minutes will the tank start to
  overflow?
• UNKNOWN time (in min.) for both pipes t fill the
  tank t
• KNOWN rate of pipe 1 is 1 tank / 6 minutes, rate
  of pipe 2 is 1 tank/8 minutes.
• RELATIONSHIP 1 job pipe 1 work pipe 2 work

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Section 7 4 Critical Thinking - Work Problems

• EQUATION 1 1 t 1 t
• 6 8
• SOLVE CD 24
• (24) 1 (1 t 1 t) (24)
• 6 8
• 24 4t 3t
• 24 t
• it would take 24 min to fill the tank

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Section 7 4 Critical Thinking - Rate Problems

• Other formulas
• Simple interest formula
• Interest Principal X Rate X Time
• I PRT
• Distance formula
• Distance Rate of speed X Time traveled
• D RT
• Pay formula
• Pay Hourly wage X Rate of pay
• P WR